Delete duplicate 'Returns' messages in the comments.

Signed-off-by: Basavesh Shivakumar <basavesh.shivakumar@gmail.com>

lib/mosquitto.h

@@ -630,10 +630,6 @@ libmosq_EXPORT int mosquitto_connect_srv(struct mosquitto *mosq, const char *hos
  * 	MOSQ_ERR_SUCCESS - on success.
  * 	MOSQ_ERR_INVAL -   if the input parameters were invalid.
  * 	MOSQ_ERR_NOMEM -   if an out of memory condition occurred.
- *
- * Returns:
- * 	MOSQ_ERR_SUCCESS - on success.
- * 	MOSQ_ERR_INVAL -   if the input parameters were invalid.
  * 	MOSQ_ERR_ERRNO -   if a system call returned an error. The variable errno
  *                     contains the error code, even on Windows.
  *                     Use strerror_r() where available or FormatMessage() on
@@ -661,10 +657,6 @@ libmosq_EXPORT int mosquitto_reconnect(struct mosquitto *mosq);
  * 	MOSQ_ERR_SUCCESS - on success.
  * 	MOSQ_ERR_INVAL -   if the input parameters were invalid.
  * 	MOSQ_ERR_NOMEM -   if an out of memory condition occurred.
- *
- * Returns:
- * 	MOSQ_ERR_SUCCESS - on success.
- * 	MOSQ_ERR_INVAL -   if the input parameters were invalid.
  * 	MOSQ_ERR_ERRNO -   if a system call returned an error. The variable errno
  *                     contains the error code, even on Windows.
  *                     Use strerror_r() where available or FormatMessage() on