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/asn1.h b/include/mbedtls/asn1.h
index 6b79196..10f7905 100644
--- a/include/mbedtls/asn1.h
+++ b/include/mbedtls/asn1.h
@@ -46,13 +46,20 @@
  * ASN1 is a standard to specify data structures.
  * \{
  */
-#define MBEDTLS_ERR_ASN1_OUT_OF_DATA                      -0x0060  /**< Out of data when parsing an ASN1 data structure. */
-#define MBEDTLS_ERR_ASN1_UNEXPECTED_TAG                   -0x0062  /**< ASN1 tag was of an unexpected value. */
-#define MBEDTLS_ERR_ASN1_INVALID_LENGTH                   -0x0064  /**< Error when trying to determine the length or invalid length. */
-#define MBEDTLS_ERR_ASN1_LENGTH_MISMATCH                  -0x0066  /**< Actual length differs from expected length. */
-#define MBEDTLS_ERR_ASN1_INVALID_DATA                     -0x0068  /**< Data is invalid. */
-#define MBEDTLS_ERR_ASN1_ALLOC_FAILED                     -0x006A  /**< Memory allocation failed */
-#define MBEDTLS_ERR_ASN1_BUF_TOO_SMALL                    -0x006C  /**< Buffer too small when writing ASN.1 data structure. */
+/** Out of data when parsing an ASN1 data structure. */
+#define MBEDTLS_ERR_ASN1_OUT_OF_DATA                      -0x0060
+/** ASN1 tag was of an unexpected value. */
+#define MBEDTLS_ERR_ASN1_UNEXPECTED_TAG                   -0x0062
+/** Error when trying to determine the length or invalid length. */
+#define MBEDTLS_ERR_ASN1_INVALID_LENGTH                   -0x0064
+/** Actual length differs from expected length. */
+#define MBEDTLS_ERR_ASN1_LENGTH_MISMATCH                  -0x0066
+/** Data is invalid. */
+#define MBEDTLS_ERR_ASN1_INVALID_DATA                     -0x0068
+/** Memory allocation failed */
+#define MBEDTLS_ERR_ASN1_ALLOC_FAILED                     -0x006A
+/** Buffer too small when writing ASN.1 data structure. */
+#define MBEDTLS_ERR_ASN1_BUF_TOO_SMALL                    -0x006C
 
 /* \} name */