nixos/rl-notes/21.11: add python3 default bump entry

nixos/doc/manual/from_md/release-notes/rl-2111.section.xml

@@ -14,12 +14,18 @@
   </itemizedlist>
   <section xml:id="sec-release-21.11-highlights">
     <title>Highlights</title>
-    <itemizedlist spacing="compact">
+    <itemizedlist>
       <listitem>
         <para>
           PHP now defaults to PHP 8.0, updated from 7.4.
         </para>
       </listitem>
+      <listitem>
+        <para>
+          <literal>python3</literal> now defaults to Python 3.9, updated
+          from Python 3.8.
+        </para>
+      </listitem>
     </itemizedlist>
   </section>
   <section xml:id="sec-release-21.11-new-services">
@@ -503,6 +509,14 @@
           <literal>rxvt-unicode</literal> explicitly.
         </para>
       </listitem>
+      <listitem>
+        <para>
+          <literal>python3</literal> now defaults to Python 3.9. Python
+          3.9 introduces many deprecation warnings, please look at the
+          <link xlink:href="https://docs.python.org/3/whatsnew/3.9.html">What’s
+          New In Python 3.9 post</link> for more information.
+        </para>
+      </listitem>
     </itemizedlist>
   </section>
 </section>

nixos/doc/manual/release-notes/rl-2111.section.md

@@ -8,6 +8,8 @@ In addition to numerous new and upgraded packages, this release has the followin
 
 - PHP now defaults to PHP 8.0, updated from 7.4.
 
+- `python3` now defaults to Python 3.9, updated from Python 3.8.
+
 ## New Services {#sec-release-21.11-new-services}
 
 - [btrbk](https://digint.ch/btrbk/index.html), a backup tool for btrfs subvolumes, taking advantage of btrfs specific capabilities to create atomic snapshots and transfer them incrementally to your backup locations. Available as [services.btrbk](options.html#opt-services.brtbk.instances).
@@ -122,3 +124,5 @@ In addition to numerous new and upgraded packages, this release has the followin
   However, if [`services.fail2ban.enable`](options.html#opt-services.fail2ban.enable) is `true`, the `fail2ban` will override the verbosity to `"VERBOSE"`, so that `fail2ban` can observe the failed login attempts from the SSH logs.
 
 - Sway: The terminal emulator `rxvt-unicode` is no longer installed by default via `programs.sway.extraPackages`. The current default configuration uses `alacritty` (and soon `foot`) so this is only an issue when using a customized configuration and not installing `rxvt-unicode` explicitly.
+
+- `python3` now defaults to Python 3.9. Python 3.9 introduces many deprecation warnings, please look at the [What's New In Python 3.9 post](https://docs.python.org/3/whatsnew/3.9.html) for more information.