manual: nginx: Remove reference to stateDir from release notes. Fixes #102211.

Fixed wording taken from:
https://github.com/NixOS/nixpkgs/issues/102211#issuecomment-719976230

nixos/doc/manual/release-notes/rl-2009.xml

@@ -879,7 +879,7 @@ php.override {
    <listitem>
      <para>
        Nginx web server now starting with additional sandbox/hardening options. By default, write access
-       to <literal>services.nginx.stateDir</literal> is allowed. To allow writing to other folders,
+       to <literal>/var/log/nginx</literal> and <literal>/var/cache/nginx</literal> is allowed. To allow writing to other folders,
        use <literal>systemd.services.nginx.serviceConfig.ReadWritePaths</literal>
        <programlisting>
 systemd.services.nginx.serviceConfig.ReadWritePaths = [ "/var/www" ];