Document more @return values with doxygen for APIs
- Note that SSH_ERROR can be returned on error in ssh_channel_get_exit_status and ssh_channel_get_session.
- Note the return codes for channel_open and grow_window; although these are internal APIs, it's best to document their behavior.
- Replace @returns use with @return. While Doxygen supports the former as a synonym for @return, it isn't documented in the manual (and might not be supported by other downstream documentation tools).
Signed-off-by: Enji Cooper <firstname.lastname@example.org>
Reviewed-by: Andreas Schneider <email@example.com>
Reviewed-by: Jakub Jelen <firstname.lastname@example.org>
Test Plan: n/a
Reviewers: #libssh, asn
Differential Revision: https://bugs.libssh.org/D15