Add some 'See also' links to IRCv3 specs where relevant

Author: progval

_includes/messages/channel.md

@@ -63,6 +63,10 @@ Message Examples:
 
       :dan-!d@localhost JOIN #test    ; dan- is joining the channel #test
 
+See also:
+
+* IRCv3 [`extended-join` Extension](https://ircv3.net/specs/extensions/extended-join)
+
 ### PART message
 
          Command: PART
@@ -148,6 +152,15 @@ Command Examples:
       NAMES #twilight_zone,#42        ; List all visible users on
                                       "#twilight_zone" and "#42".
 
+      NAMES                           ; Attempt to list all visible users on
+                                      the network, which SHOULD be responded to
+                                      as specified above.
+
+See also:
+
+* IRCv3 [`multi-prefix` Extension](https://ircv3.net/specs/extensions/multi-prefix)
+* IRCv3 [`userhost-in-names` Extension](https://ircv3.net/specs/extensions/userhost-in-names)
+
 ### LIST message
 
          Command: LIST
@@ -218,6 +231,10 @@ Message Examples:
       :dan-!d@localhost INVITE Wiz #test    ; dan- has invited Wiz
                                             to the channel #test
 
+See also:
+
+* IRCv3 [`invite-notify` Extension](https://ircv3.net/specs/extensions/invite-notify)
+
 #### Invite list
 
 Servers MAY allow the `INVITE` with no parameter, and reply with a list of channels the sender is invited to as {% numeric RPL_INVITELIST %} numerics, ending with a {% numeric RPL_ENDOFINVITELIST %} numeric.

_includes/messages/server_queries.md

@@ -138,6 +138,10 @@ Command Examples:
       :Angel TIME *.au                ; user angel checking the time on a
                                       server matching "*.au"
 
+See also:
+
+* IRCv3 [`server-time` Extension](https://ircv3.net/specs/extensions/server-time)
+
 ### STATS message
 
          Command: STATS

_includes/messages/user_queries.md

@@ -21,6 +21,11 @@ Numeric Replies:
 * {% numeric RPL_ENDOFWHO %}
 * {% numeric ERR_NOSUCHSERVER %}
 
+See also:
+
+* IRCv3 [`multi-prefix` Extension](https://ircv3.net/specs/extensions/multi-prefix)
+* [WHOX](https://ircv3.net/specs/extensions/whox)
+
 #### Examples
 
 Command Examples:
@@ -97,6 +102,8 @@ They exist mainly on historical servers, and are rarely implemented, because of
 
 * Servers MAY allow wildcards in `<nick>`. Servers who do SHOULD reply with information about all matching nicks. They may restrict what information is available in this case, to limit resource usage.
 
+* IRCv3 [`multi-prefix` Extension](https://ircv3.net/specs/extensions/multi-prefix)
+
 #### Examples
 
 Command Examples: