Update sha1.h

Minor documentation improvements:
*Standardized file brief description.
*Separated return statements.
*Reordered tags within documentation blocks so that params and returns are last in block.
*Applied previous function documentation improvements to depracated functions.
diff --git a/include/mbedtls/sha1.h b/include/mbedtls/sha1.h
index 05540cd..4a43c01 100644
--- a/include/mbedtls/sha1.h
+++ b/include/mbedtls/sha1.h
@@ -1,7 +1,10 @@
 /**
  * \file sha1.h
  *
- * \brief The SHA-1 cryptographic hash function.
+ * \brief This file contains SHA-1 definitions and functions.
+ *
+ * The Secure Hash Algorithm 1 (SHA-1) cryptographic hash function is defined in 
+ * <em>FIPS 180-4: Secure Hash Standard (SHS)</em>.
  *
  * \warning   SHA-1 is considered a weak message digest and its use constitutes
  *            a security risk. We recommend considering stronger message
@@ -66,37 +69,37 @@
 /**
  * \brief          This function initializes a SHA-1 context.
  *
- * \param ctx      The SHA-1 context to initialize.
- *
  * \warning        SHA-1 is considered a weak message digest and its use
  *                 constitutes a security risk. We recommend considering
  *                 stronger message digests instead.
  *
+ * \param ctx      The SHA-1 context to initialize.
+ *
  */
 void mbedtls_sha1_init( mbedtls_sha1_context *ctx );
 
 /**
  * \brief          This function clears a SHA-1 context.
  *
- * \param ctx      The SHA-1 context to clear.
- *
  * \warning        SHA-1 is considered a weak message digest and its use
  *                 constitutes a security risk. We recommend considering
  *                 stronger message digests instead.
  *
+ * \param ctx      The SHA-1 context to clear.
+ *
  */
 void mbedtls_sha1_free( mbedtls_sha1_context *ctx );
 
 /**
  * \brief          This function clones the state of a SHA-1 context.
  *
- * \param dst      The destination context.
- * \param src      The context to clone.
- *
  * \warning        SHA-1 is considered a weak message digest and its use
  *                 constitutes a security risk. We recommend considering
  *                 stronger message digests instead.
  *
+ * \param dst      The destination context.
+ * \param src      The context to clone.
+ *
  */
 void mbedtls_sha1_clone( mbedtls_sha1_context *dst,
                          const mbedtls_sha1_context *src );
@@ -104,14 +107,14 @@
 /**
  * \brief          This function starts a SHA-1 checksum calculation.
  *
- * \param ctx      The context to initialize.
- *
- * \return         \c 0 if successful
- *
  * \warning        SHA-1 is considered a weak message digest and its use
  *                 constitutes a security risk. We recommend considering
  *                 stronger message digests instead.
  *
+ * \param ctx      The context to initialize.
+ *
+ * \return         \c 0 on success.
+ *
  */
 int mbedtls_sha1_starts_ret( mbedtls_sha1_context *ctx );
 
@@ -119,16 +122,15 @@
  * \brief          This function feeds an input buffer into an ongoing SHA-1
  *                 checksum calculation.
  *
- * \param ctx      The SHA-1 context.
- * \param input    The buffer holding the input data.
- * \param ilen     The length of the input data.
- *
- * \return         \c 0 if successful
- *
  * \warning        SHA-1 is considered a weak message digest and its use
  *                 constitutes a security risk. We recommend considering
  *                 stronger message digests instead.
  *
+ * \param ctx      The SHA-1 context.
+ * \param input    The buffer holding the input data.
+ * \param ilen     The length of the input data.
+ *
+ * \return         \c 0 on success.
  */
 int mbedtls_sha1_update_ret( mbedtls_sha1_context *ctx,
                              const unsigned char *input,
@@ -138,31 +140,30 @@
  * \brief          This function finishes the SHA-1 operation, and writes
  *                 the result to the output buffer.
  *
- * \param ctx      The SHA-1 context.
- * \param output   The SHA-1 checksum result.
- *
- * \return         \c 0 if successful
- *
  * \warning        SHA-1 is considered a weak message digest and its use
  *                 constitutes a security risk. We recommend considering
  *                 stronger message digests instead.
  *
+ * \param ctx      The SHA-1 context.
+ * \param output   The SHA-1 checksum result.
+ *
+ * \return         \c 0 on success.
  */
 int mbedtls_sha1_finish_ret( mbedtls_sha1_context *ctx,
                              unsigned char output[20] );
 
 /**
- * \brief          SHA-1 process data block (internal use only)
- *
- * \param ctx      SHA-1 context
- * \param data     The data block being processed.
- *
- * \return         \c 0 if successful
+ * \brief          SHA-1 process data block (internal use only).
  *
  * \warning        SHA-1 is considered a weak message digest and its use
  *                 constitutes a security risk. We recommend considering
  *                 stronger message digests instead.
  *
+ * \param ctx      The SHA-1 context.
+ * \param data     The data block being processed.
+ *
+ * \return         \c 0 on success.
+ *
  */
 int mbedtls_internal_sha1_process( mbedtls_sha1_context *ctx,
                                    const unsigned char data[64] );
@@ -174,65 +175,67 @@
 #define MBEDTLS_DEPRECATED
 #endif
 /**
- * \brief          SHA-1 context setup
- *
- * \deprecated     Superseded by mbedtls_sha1_starts_ret() in 2.7.0
- *
- * \param ctx      The SHA-1 context to be initialized.
+ * \brief          This function starts a SHA-1 checksum calculation.
  *
  * \warning        SHA-1 is considered a weak message digest and its use
  *                 constitutes a security risk. We recommend considering
  *                 stronger message digests instead.
  *
+ * \deprecated     Superseded by mbedtls_sha1_starts_ret() in 2.7.0.
+ *
+ * \param ctx      The context to initialize.
+ *
  */
 MBEDTLS_DEPRECATED void mbedtls_sha1_starts( mbedtls_sha1_context *ctx );
 
 /**
- * \brief          SHA-1 process buffer
- *
- * \deprecated     Superseded by mbedtls_sha1_update_ret() in 2.7.0
- *
- * \param ctx      The SHA-1 context.
- * \param input    The buffer holding the input data.
- * \param ilen     The length of the input data.
+ * \brief          This function feeds an input buffer into an ongoing SHA-1
+ *                 checksum calculation.
  *
  * \warning        SHA-1 is considered a weak message digest and its use
  *                 constitutes a security risk. We recommend considering
  *                 stronger message digests instead.
  *
+ * \deprecated     Superseded by mbedtls_sha1_update_ret() in 2.7.0.
+ *
+ * \param ctx      The SHA-1 context.
+ * \param input    The buffer holding the input data.
+ * \param ilen     The length of the input data.
+ *
  */
 MBEDTLS_DEPRECATED void mbedtls_sha1_update( mbedtls_sha1_context *ctx,
                                              const unsigned char *input,
                                              size_t ilen );
 
 /**
- * \brief          SHA-1 final digest
- *
- * \deprecated     Superseded by mbedtls_sha1_finish_ret() in 2.7.0
- *
- * \param ctx      The SHA-1 context.
- * \param output   The SHA-1 checksum result.
+ * \brief          This function finishes the SHA-1 operation, and writes
+ *                 the result to the output buffer.
  *
  * \warning        SHA-1 is considered a weak message digest and its use
  *                 constitutes a security risk. We recommend considering
  *                 stronger message digests instead.
  *
+ * \deprecated     Superseded by mbedtls_sha1_finish_ret() in 2.7.0.
+ *
+ * \param ctx      The SHA-1 context.
+ * \param output   The SHA-1 checksum result.
+ *
  */
 MBEDTLS_DEPRECATED void mbedtls_sha1_finish( mbedtls_sha1_context *ctx,
                                              unsigned char output[20] );
 
 /**
- * \brief          SHA-1 process data block (internal use only)
- *
- * \deprecated     Superseded by mbedtls_internal_sha1_process() in 2.7.0
- *
- * \param ctx      The SHA-1 context.
- * \param data     The data block being processed.
+ * \brief          SHA-1 process data block (internal use only).
  *
  * \warning        SHA-1 is considered a weak message digest and its use
  *                 constitutes a security risk. We recommend considering
  *                 stronger message digests instead.
  *
+ * \deprecated     Superseded by mbedtls_internal_sha1_process() in 2.7.0.
+ *
+ * \param ctx      The SHA-1 context.
+ * \param data     The data block being processed.
+ *
  */
 MBEDTLS_DEPRECATED void mbedtls_sha1_process( mbedtls_sha1_context *ctx,
                                               const unsigned char data[64] );
@@ -261,15 +264,15 @@
  *                 The SHA-1 result is calculated as
  *                 output = SHA-1(input buffer).
  *
+ * \warning        SHA-1 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
+ *
  * \param input    The buffer holding the input data.
  * \param ilen     The length of the input data.
  * \param output   The SHA-1 checksum result.
  *
- * \return         \c 0 if successful
- *
- * \warning        SHA-1 is considered a weak message digest and its use
- *                 constitutes a security risk. We recommend considering
- *                 stronger message digests instead.
+ * \return         \c 0 on success.
  *
  */
 int mbedtls_sha1_ret( const unsigned char *input,
@@ -283,7 +286,17 @@
 #define MBEDTLS_DEPRECATED
 #endif
 /**
- * \brief          Output = SHA-1( input buffer )
+* \brief          This function calculates the SHA-1 checksum of a buffer.
+ *
+ *                 The function allocates the context, performs the
+ *                 calculation, and frees the context.
+ *
+ *                 The SHA-1 result is calculated as
+ *                 output = SHA-1(input buffer).
+ *
+ * \warning        SHA-1 is considered a weak message digest and its use
+ *                 constitutes a security risk. We recommend considering
+ *                 stronger message digests instead.
  *
  * \deprecated     Superseded by mbedtls_sha1_ret() in 2.7.0
  *
@@ -291,10 +304,6 @@
  * \param ilen     The length of the input data.
  * \param output   The SHA-1 checksum result.
  *
- * \warning        SHA-1 is considered a weak message digest and its use
- *                 constitutes a security risk. We recommend considering
- *                 stronger message digests instead.
- *
  */
 MBEDTLS_DEPRECATED void mbedtls_sha1( const unsigned char *input,
                                       size_t ilen,
@@ -306,12 +315,13 @@
 /**
  * \brief          The SHA-1 checkup routine.
  *
- * \return         \c 0 on success, or \c 1 on failure.
- *
  * \warning        SHA-1 is considered a weak message digest and its use
  *                 constitutes a security risk. We recommend considering
  *                 stronger message digests instead.
  *
+ * \return         \c 0 on success.
+ * \return         \c 1 on failure.
+ *
  */
 int mbedtls_sha1_self_test( int verbose );