Add changelog for 3.5.0-RC5

Author: WojciechMazur

changelogs/3.5.0-RC5.md

@@ -0,0 +1,14 @@
+# Backported fixes
+
+- emit generatedNonLocalClass in backend when callback is not enabled [#21186](https://github.com/scala/scala3/pull/21186)
+
+# Contributors
+
+Thank you to all the contributors who made this release possible 🎉
+
+According to `git shortlog -sn --no-merges 3.5.0-RC4..3.5.0-RC5` these are:
+
+```
+     2  Jamie Thompson
+     2  Wojciech Mazur
+```