Add the changelog entry for #1576

changelog.d/1576-transit-bikeshare-coverage-prompt.md

@@ -0,0 +1,6 @@
+- Say why Transit and Bike Share are empty outside coverage. Over a city with
+  no feed or system (London, Tokyo) their Layers rows read
+  `No feed here yet · 16 regions available` and
+  `No bike share here yet · 61 systems available`, or how low to fly, instead
+  of `never`; leaving coverage clears the last-update time (German, @gekh,
+  #1576).