Add missing changelog entry

Author: Ortham

CHANGELOG.md

@@ -47,6 +47,11 @@ changelog does not include libloadorder-ffi changes.
   blueprint plugins, or of BlueprintShips plugins that are not
   blueprint-flagged.
 
+- `WritableLoadOrder::is_ambiguous()` now ignores blueprint plugins and
+  BlueprintShips plugins for Starfield, since it's not possible to stop the game
+  from making their load order positions ambiguous, so returning true when they
+  are ambiguous can hide ambiguity that is permanently resolvable.
+
 ## [18.5.1] - 2025-09-29
 
 ### Changed