Update doc on banning disruptive users for OFTC

OFTC doesn't have a server-side remove command (I can't find
evidence that it even works on Freenode though I only bothered to
test on OFTC to confirm). Update this section of our IRC document
accordingly.

Change-Id: I6b7838327f0d4ea3ea8c3697fc784657bb2a64ff

doc/source/irc.rst

@@ -312,19 +312,9 @@ channel is to add them to Chanserv's auto-kick list like so::
 This will immediately and anonymously kick them from the channel, and prevent
 them from rejoining until explicitly removed from the akick list again.
 
-On some networks, the preferred mechanism for removing a user from a channel is
-a kick. Freenode also supports the "remove" command which is a gentler way to
-simply send a part-like command to the user's client. In most cases, this will
-signal the client not to try to rejoin. Syntax for the removal command is as
-follows (you must be an operator)::
-
-  /quote remove #channel nickname :Reason goes here
-
-Note the colon in the syntax, if this is omitted only the first word will
-accompany the removal message.
-
 Banning of disruptive users is also available with the `/ban` command, see your
-client documentation for syntax.
+client documentation for syntax, though this will require opping yourself in
+the channel first.
 
 Renaming an IRC Channel
 =======================