Improve release notes

doc/manual/src/release-notes/rl-next.md

@@ -3,4 +3,13 @@
 * The `repeat` and `enforce-determinism` options have been removed
   since they had been broken under many circumstances for a long time.
 
-* Allow explicitly selecting outputs with *store derivations* installable syntax too.
+* Allow explicitly selecting outputs in a store derivation installable, just like we can do with other sorts of installables.
+  For example,
+  ```shell-session
+  $ nix-build /nix/store/gzaflydcr6sb3567hap9q6srzx8ggdgg-glibc-2.33-78.drv^dev`
+  ```
+  now works just as
+  ```shell-session
+  $ nix-build glibc^dev`
+  ```
+  does already.