Merge pull request #198336 from ck3d/doc-overrideStrategy

doc/rl-2211: add new option overrideStrategy

nixos/doc/manual/from_md/release-notes/rl-2211.section.xml

···
       </listitem>
       <listitem>
         <para>
+          The option <literal>overrideStrategy</literal> was added to
+          the different systemd unit options
+          (<literal>systemd.services.&lt;name&gt;</literal>,
+          <literal>systemd.sockets.&lt;name&gt;</literal>, …) to allow
+          enforcing the creation of a dropin file, rather than the main
+          unit file, by setting it to <literal>asDropin</literal>. This
+          is useful in cases where the existence of the main unit file
+          is not known to Nix at evaluation time, for example when the
+          main unit file is provided by adding a package to
+          <literal>systemd.packages</literal>. See the fix proposed in
+          <link xlink:href="https://github.com/NixOS/nixpkgs/issues/135557#issuecomment-1295392470">NixOS’s
+          systemd abstraction doesn’t work with systemd template
+          units</link> for an example.
+        </para>
+      </listitem>
+      <listitem>
+        <para>
           The <literal>polymc</literal> package has been removed due to
           a rogue maintainer. It has been replaced by
           <literal>prismlauncher</literal>, a fork by the rest of the

nixos/doc/manual/release-notes/rl-2211.section.md

···
 
 - The `networking.wireguard` module now can set the mtu on interfaces and tag its packets with an fwmark.
 
+- The option `overrideStrategy` was added to the different systemd unit options (`systemd.services.<name>`, `systemd.sockets.<name>`, …) to allow enforcing the creation of a dropin file, rather than the main unit file, by setting it to `asDropin`.
+  This is useful in cases where the existence of the main unit file is not known to Nix at evaluation time, for example when the main unit file is provided by adding a package to `systemd.packages`.
+  See the fix proposed in [NixOS's systemd abstraction doesn't work with systemd template units](https://github.com/NixOS/nixpkgs/issues/135557#issuecomment-1295392470) for an example.
+
 - The `polymc` package has been removed due to a rogue maintainer. It has been
   replaced by `prismlauncher`, a fork by the rest of the maintainers. For more
   details, see [the pull request that made this