GUAC-1389: Add missing parameter documentation for user-level instruction handlers.
GUAC-1389: Add missing parameter documentation for user-level instruction handlers.

flangelo/guacamole-server,mike-jumper/incubator-guacamole-server,mike-jumper/incubator-guacamole-server,flangelo/guacamole-server,apache/guacamole-server,apache/guacamole-server,glyptodon/guacamole-server,flangelo/guacamole-server,mike-jumper/incubator-guacamole-server,glyptodon/guacamole-server,apache/guacamole-server,glyptodon/guacamole-server,flangelo/guacamole-server,mike-jumper/incubator-guacamole-server