Revert "docs/website/support.html: document irc channel permission changes"

This didn't work out as planned, neither the restriction of muting
unregistered users, nor the exception for matrix users worked as planned.

The channel mode has been reverted to +R (meaning only registered users
are allowed to join) and an exception for *that* has been introduced for
matrix users via +e. The channel modes are documented in [1].

[1] https://www.oftc.net/ChannelModes/

This reverts commit d1e6d7845b0f3b450709b84a6e4fc4527f12b196.

Signed-off-by: Marcus Hoffmann <buildroot@bubu1.eu>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

docs/website/support.html

@@ -27,8 +27,8 @@
 		    When asking for help on IRC, share relevant logs or pieces of code using a code
 		    sharing website.</p>
 
-		  <p>Note that due to excessive spamming on IRC, you can only talk in the
-		    channel if you are a registered user with
+		  <p>Note that due to excessive spamming on IRC, the channel can only be
+		    joined if you are a registered user with
 		    <a href="https://www.oftc.net/Services/">OFTC NickServ</a>
 		    service. Follow the instructions to register as a user with a password,
 		    and then join the <code>#buildroot</code> channel.</p>