fix channel mode help text

irc/help.go

@@ -55,7 +55,7 @@ Oragono supports the following channel modes:
   +E  |  Roleplaying commands are enabled in the channel.
   +C  |  Clients are blocked from sending CTCP messages in the channel.
   +u  |  Auditorium mode: JOIN, PART, QUIT, NAMES, and WHO are hidden
-         hidden from unvoiced clients.
+         from unvoiced clients.
   +U  |  Op-moderated mode: messages from unprivileged clients are sent
          only to channel operators.