meta: add release note for starship module update

nixos/doc/manual/release-notes/rl-2505.section.md

@@ -58,6 +58,6 @@
 
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-- Create the first release note entry in this section!
+- The [Starship](https://starship.rs) module now automatically loads the starship prompt when using [`xonsh`](https://xon.sh).
 
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