do not use plural in ace comment

src/common/config.py

@@ -154,8 +154,8 @@ class Config:
 		'autodetect_browser_mailer': [opt_bool, False, '', True],
 		'print_ichat_every_foo_minutes': [opt_int, 5, _('When not printing time for every message (print_time==sometimes), print it every x minutes.')],
 		'confirm_close_muc': [opt_bool, True, _('Ask before closing a group chat tab/window.')],
-		'confirm_close_muc_rooms': [opt_str, '', _('Always ask before closing group chat tab/window in this space separated list of group chats jids.')],
-		'noconfirm_close_muc_rooms': [opt_str, '', _('Never ask before closing group chat tab/window in this space separated list of group chats jids.')],
+		'confirm_close_muc_rooms': [opt_str, '', _('Always ask before closing group chat tab/window in this space separated list of group chat jids.')],
+		'noconfirm_close_muc_rooms': [opt_str, '', _('Never ask before closing group chat tab/window in this space separated list of group chat jids.')],
 		'notify_on_file_complete': [opt_bool, True],
 		'file_transfers_port': [opt_int, 28011],
 		'ft_override_host_to_send': [opt_str, '', _('Overrides the host we send for File Transfer in case of address translation/port forwarding.')],