Move MBEDTLS_ERR_xxx Doxygen comments before the definition

Now that descriptions of error codes no longer have to be on the same line
for the sake of generate_errors.pl, move them to their own line before the
definition. This aligns them with what we do for other definitions, and
means that we no longer need to have very long lines containing both the C
definition and the comment.

```
perl -i -pe 's~^(#define +MBEDTLS_ERR_\w+ +-\w+) */\*[*!]<(.*)\*/~/**$2*/\n$1~' include/mbedtls/*.h
```

This commit does not change the output of generate_errors.pl.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/include/mbedtls/pk.h b/include/mbedtls/pk.h
index 7d0f977..8f2abf2 100644
--- a/include/mbedtls/pk.h
+++ b/include/mbedtls/pk.h
@@ -52,23 +52,38 @@
 #define inline __inline
 #endif
 
-#define MBEDTLS_ERR_PK_ALLOC_FAILED        -0x3F80  /**< Memory allocation failed. */
-#define MBEDTLS_ERR_PK_TYPE_MISMATCH       -0x3F00  /**< Type mismatch, eg attempt to encrypt with an ECDSA key */
-#define MBEDTLS_ERR_PK_BAD_INPUT_DATA      -0x3E80  /**< Bad input parameters to function. */
-#define MBEDTLS_ERR_PK_FILE_IO_ERROR       -0x3E00  /**< Read/write of file failed. */
-#define MBEDTLS_ERR_PK_KEY_INVALID_VERSION -0x3D80  /**< Unsupported key version */
-#define MBEDTLS_ERR_PK_KEY_INVALID_FORMAT  -0x3D00  /**< Invalid key tag or value. */
-#define MBEDTLS_ERR_PK_UNKNOWN_PK_ALG      -0x3C80  /**< Key algorithm is unsupported (only RSA and EC are supported). */
-#define MBEDTLS_ERR_PK_PASSWORD_REQUIRED   -0x3C00  /**< Private key password can't be empty. */
-#define MBEDTLS_ERR_PK_PASSWORD_MISMATCH   -0x3B80  /**< Given private key password does not allow for correct decryption. */
-#define MBEDTLS_ERR_PK_INVALID_PUBKEY      -0x3B00  /**< The pubkey tag or value is invalid (only RSA and EC are supported). */
-#define MBEDTLS_ERR_PK_INVALID_ALG         -0x3A80  /**< The algorithm tag or value is invalid. */
-#define MBEDTLS_ERR_PK_UNKNOWN_NAMED_CURVE -0x3A00  /**< Elliptic curve is unsupported (only NIST curves are supported). */
-#define MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE -0x3980  /**< Unavailable feature, e.g. RSA disabled for RSA key. */
-#define MBEDTLS_ERR_PK_SIG_LEN_MISMATCH    -0x3900  /**< The buffer contains a valid signature followed by more data. */
+/** Memory allocation failed. */
+#define MBEDTLS_ERR_PK_ALLOC_FAILED        -0x3F80
+/** Type mismatch, eg attempt to encrypt with an ECDSA key */
+#define MBEDTLS_ERR_PK_TYPE_MISMATCH       -0x3F00
+/** Bad input parameters to function. */
+#define MBEDTLS_ERR_PK_BAD_INPUT_DATA      -0x3E80
+/** Read/write of file failed. */
+#define MBEDTLS_ERR_PK_FILE_IO_ERROR       -0x3E00
+/** Unsupported key version */
+#define MBEDTLS_ERR_PK_KEY_INVALID_VERSION -0x3D80
+/** Invalid key tag or value. */
+#define MBEDTLS_ERR_PK_KEY_INVALID_FORMAT  -0x3D00
+/** Key algorithm is unsupported (only RSA and EC are supported). */
+#define MBEDTLS_ERR_PK_UNKNOWN_PK_ALG      -0x3C80
+/** Private key password can't be empty. */
+#define MBEDTLS_ERR_PK_PASSWORD_REQUIRED   -0x3C00
+/** Given private key password does not allow for correct decryption. */
+#define MBEDTLS_ERR_PK_PASSWORD_MISMATCH   -0x3B80
+/** The pubkey tag or value is invalid (only RSA and EC are supported). */
+#define MBEDTLS_ERR_PK_INVALID_PUBKEY      -0x3B00
+/** The algorithm tag or value is invalid. */
+#define MBEDTLS_ERR_PK_INVALID_ALG         -0x3A80
+/** Elliptic curve is unsupported (only NIST curves are supported). */
+#define MBEDTLS_ERR_PK_UNKNOWN_NAMED_CURVE -0x3A00
+/** Unavailable feature, e.g. RSA disabled for RSA key. */
+#define MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE -0x3980
+/** The buffer contains a valid signature followed by more data. */
+#define MBEDTLS_ERR_PK_SIG_LEN_MISMATCH    -0x3900
 
 /* MBEDTLS_ERR_PK_HW_ACCEL_FAILED is deprecated and should not be used. */
-#define MBEDTLS_ERR_PK_HW_ACCEL_FAILED     -0x3880  /**< PK hardware accelerator failed. */
+/** PK hardware accelerator failed. */
+#define MBEDTLS_ERR_PK_HW_ACCEL_FAILED     -0x3880
 
 #ifdef __cplusplus
 extern "C" {