Add missing return documentation

Author: punkymaniac

include/git2/remote.h

@@ -253,6 +253,7 @@ GIT_EXTERN(int) git_remote_set_url(git_repository *repo, const char *remote, con
  * @param repo the repository in which to perform the change
  * @param remote the remote's name
  * @param url the url to set
+ * @return 0, or an error code
  */
 GIT_EXTERN(int) git_remote_set_pushurl(git_repository *repo, const char *remote, const char* url);
 
@@ -876,6 +877,7 @@ GIT_EXTERN(git_remote_autotag_option_t) git_remote_autotag(const git_remote *rem
  * @param repo the repository in which to make the change
  * @param remote the name of the remote
  * @param value the new value to take.
+ * @return 0, or an error code.
  */
 GIT_EXTERN(int) git_remote_set_autotag(git_repository *repo, const char *remote, git_remote_autotag_option_t value);