Add extended-isupport and network-icon (#573)

Author: emersion

_data/irc_versions.yml

@@ -251,6 +251,14 @@ stable:
       caps:
         - draft/chathistory
 
+    extended-isupport:
+      name: draft/extended-isupport
+      description: extended-isupport Extension DRAFT
+      link: /specs/extensions/extended-isupport.html
+      draft: true
+      caps:
+        - draft/extended-isupport
+
     message-redaction:
       name: draft/message-redaction
       description: Message redaction DRAFT
@@ -259,6 +267,12 @@ stable:
       caps:
         - draft/message-redaction
 
+    network-icon:
+      name: draft/network-icon
+      description: Network Icon DRAFT
+      link: /specs/extensions/network-icon.html
+      draft: true
+
     react-client-tag:
       name: +draft/react
       description: React client tag DRAFT

_data/registry.yml

@@ -193,6 +193,10 @@
       specs:
         - chathistory
       description: Lets clients request JOIN/MODE/etc messages as part of history.
+    - name: extended-isupport
+      specs:
+        - extended-isupport
+      description: Enables clients to request ISUPPORT before connection registration.
     - name: extended-join
       specs:
         - extended-join
@@ -345,6 +349,11 @@
         - netsplitjoin-batch
       description: Indicates that the given clients are quitting as the result of a netsplit (two servers disconnecting).
 
+    - name: draft/isupport
+      specs:
+        - extended-isupport
+      description: Indicates that the given messages belong to a single ISUPPORT burst.
+
 - name: Messages
   include_numeric: false
   include_specs: true
@@ -378,6 +387,10 @@
       specs: 
         - invite-notify
       description: Not defined by IRCv3 but extended to alert other clients that someone's been invited to one of their channels.
+    - name: ISUPPORT
+      specs:
+        - extended-isupport
+      description: Requests ISUPPORT server information.
     - name: JOIN
       specs: 
         - extended-join
@@ -462,3 +475,8 @@
       specs:
         - whox
       description: Indicates the server supports the extended WHO syntax
+
+    - name: draft/ICON
+      specs:
+        - network-icon
+      description: Advertises a server icon.

_irc/index.md

@@ -250,6 +250,17 @@ describes the new `INVITE` reply which this extension uses, and how clients
 interpret these notifications.
 
 
+## `ISUPPORT`
+
+The **work-in-progress** [`extended-isupport` spec]({{site.baseurl}}/specs/extensions/extended-isupport.html)
+allows clients to fetch the `ISUPPORT` metadata prior to connection
+registration, introduces a new command to fetch `ISUPPORT` and a new batch type
+to delimit `ISUPPORT` bursts.
+
+The **work-in-progress** [network icon spec]({{site.baseurl}}/specs/extensions/network-icon.html)
+introduces a new `ISUPPORT` token to advertise a network icon.
+
+
 ## [Labeled Responses]({{site.baseurl}}/specs/extensions/labeled-response.html)
 
 The `labeled-response` extension allows clients to link returned numerics with