release-notes: Add notice regarding dropped Emacs aliases

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

@@ -624,6 +624,14 @@
           move all files to the new directory.
         </para>
       </listitem>
+      <listitem>
+        <para>
+          Deprecated package aliases in <literal>emacs.pkgs.*</literal>
+          have been removed. These aliases were remnants of the old
+          Emacs package infrastructure. We now use exact upstream names
+          wherever possible.
+        </para>
+      </listitem>
     </itemizedlist>
   </section>
   <section xml:id="sec-release-21.11-notable-changes">

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

@@ -157,6 +157,8 @@ pt-services.clipcat.enable).
 
 - `services.uptimed` now uses `/var/lib/uptimed` as its stateDirectory instead of `/var/spool/uptimed`. Make sure to move all files to the new directory.
 
+- Deprecated package aliases in `emacs.pkgs.*` have been removed. These aliases were remnants of the old Emacs package infrastructure. We now use exact upstream names wherever possible.
+
 ## Other Notable Changes {#sec-release-21.11-notable-changes}
 
 - The setting [`services.openssh.logLevel`](options.html#opt-services.openssh.logLevel) `"VERBOSE"` `"INFO"`. This brings NixOS in line with upstream and other Linux distributions, and reduces log spam on servers due to bruteforcing botnets.