Add changelog entry

CHANGELOG.md

@@ -53,6 +53,7 @@
     Bug #7243: Get Skyrim.esm loading
     Bug #7298: Water ripples from projectiles sometimes are not spawned
     Bug #7307: Alchemy "Magic Effect" search string does not match on tool tip for effects related to attributes
+    Bug #7413: Generated wilderness cells don't spawn fish
     Bug #7415: Unbreakable lock discrepancies
     Feature #3537: Shader-based water ripples
     Feature #5492: Let rain and snow collide with statics