Move the changelog entry into changelog.d

Main now takes release notes as one fragment per pull request (#787).

CHANGELOG.md

@@ -1,11 +1,5 @@
 # Changelog
 
-- Fire-perimeter queries handle outlines and holes crossing the antimeridian:
-  areas enclosed near ±180° are included, areas at the opposite meridian are
-  excluded, and returned perimeter coordinates stay near the dateline. Incident
-  cards use the same circular longitude mean and compare multipart outline
-  areas along short longitude edges, keeping the card on the largest polygon.
-
 - Local FM seek finds stations after wrapping around 87.5–108 MHz, covers both
   band edges, skips the starting station and rejects spectra from an earlier
   tune (Aditya, @Rohilalala, #1174).

changelog.d/1142-antimeridian-fire-perimeters.md

@@ -0,0 +1,6 @@
+- Fire-perimeter queries handle outlines and holes crossing the antimeridian:
+  areas enclosed near ±180° are included, areas at the opposite meridian are
+  excluded, and returned perimeter coordinates stay near the dateline. Incident
+  cards use the same circular longitude mean and compare multipart outline
+  areas along short longitude edges, keeping the card on the largest polygon
+  (Arianna Method, @ariannamethod, #1142).