[gnome-user-docs] gnome-help: Remove comment about removed "Availability" functionality

[Andre Klapper <aklapper src gnome org>]

commit e8884589bd90314d8e4ce425b4869e8cc8f6ae0d
Author: Andre Klapper <a9016009 gmx de>
Date:   Sun Feb 23 21:40:08 2020 +0100

    gnome-help: Remove comment about removed "Availability" functionality

 gnome-help/C/shell-introduction.page | 20 ++------------------
 1 file changed, 2 insertions(+), 18 deletions(-)
---
diff --git a/gnome-help/C/shell-introduction.page b/gnome-help/C/shell-introduction.page
index 0eb621d6..a28bae40 100644
--- a/gnome-help/C/shell-introduction.page
+++ b/gnome-help/C/shell-introduction.page
@@ -216,28 +216,12 @@ like "Application windows" by using if:when and if:else ? -->
   <p>Click the system menu in the top-right corner to manage your system
   settings and your computer.</p>
 
-<!-- Apparently not anymore. TODO: figure out how to update status.
-  <p>You can quickly set your availability directly from the menu. This will set
-  your status for your contacts to see in instant messaging applications such as
-  <app>Empathy</app>.</p>-->
-
-<comment>
-<cite date="2012-02-19">shaunm</cite>
-  <p>These are separate now. Write another blurb about "Notifications".
-  I'm also dropping shell-session-status UNTIL the docs for this get
-  cleared up. It was orphaned and incorrect.</p>
-</comment>
-
-<!--
+<!-- TODO: Update for 3.36 UI option "Do Not Disturb" in calendar dropdown:
+
 <p>If you set yourself to Unavailable, you won’t be bothered by message popups
 at the bottom of your screen. Messages will still be available in the message
 tray when you move your mouse to the bottom-right corner. But only urgent
 messages will be presented, such as when your battery is critically low.</p>
-
-<list style="compact">
-  <item><p><link xref="shell-session-status">Learn more about changing
-  your availability.</link></p></item>
-</list>
 -->
 
   <p>When you leave your computer, you can lock your screen to prevent other