json: Improve help meta command in gpgme-json.
json: Improve help meta command in gpgme-json.

* src/gpgme-json.c (process_meta_commands): Add ",help CMD".

Signed-off-by: Werner Koch <13bd1fc5137f503b0a8355ad400e7a87ebb45b25@gnupg.org>

gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme,gpg/gpgme