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/aria.h b/include/mbedtls/aria.h
index 6c73d10..226e2db 100644
--- a/include/mbedtls/aria.h
+++ b/include/mbedtls/aria.h
@@ -50,16 +50,20 @@
 #if !defined(MBEDTLS_DEPRECATED_REMOVED)
 #define MBEDTLS_ERR_ARIA_INVALID_KEY_LENGTH   MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( -0x005C )
 #endif /* !MBEDTLS_DEPRECATED_REMOVED */
-#define MBEDTLS_ERR_ARIA_BAD_INPUT_DATA -0x005C /**< Bad input data. */
+/** Bad input data. */
+#define MBEDTLS_ERR_ARIA_BAD_INPUT_DATA -0x005C
 
-#define MBEDTLS_ERR_ARIA_INVALID_INPUT_LENGTH -0x005E /**< Invalid data input length. */
+/** Invalid data input length. */
+#define MBEDTLS_ERR_ARIA_INVALID_INPUT_LENGTH -0x005E
 
 /* MBEDTLS_ERR_ARIA_FEATURE_UNAVAILABLE is deprecated and should not be used.
  */
-#define MBEDTLS_ERR_ARIA_FEATURE_UNAVAILABLE  -0x005A  /**< Feature not available. For example, an unsupported ARIA key size. */
+/** Feature not available. For example, an unsupported ARIA key size. */
+#define MBEDTLS_ERR_ARIA_FEATURE_UNAVAILABLE  -0x005A
 
 /* MBEDTLS_ERR_ARIA_HW_ACCEL_FAILED is deprecated and should not be used. */
-#define MBEDTLS_ERR_ARIA_HW_ACCEL_FAILED      -0x0058  /**< ARIA hardware accelerator failed. */
+/** ARIA hardware accelerator failed. */
+#define MBEDTLS_ERR_ARIA_HW_ACCEL_FAILED      -0x0058
 
 #ifdef __cplusplus
 extern "C" {