Move the changelog entry into changelog.d

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

changelog.d/1097-overpass-remark-failure-phrases.md

@@ -0,0 +1,5 @@
+- Overpass data whose element tags contain a failure phrase ("timed out",
+  "runtime error", "too many requests" and similar, e.g. a place named "Timed
+  Out Escape Rooms") is returned as data instead of being refused and putting
+  the endpoint on cooldown; upstream failures are read from the remark (Aditya,
+  @Rohilalala, #1097).