Tighten coverage prompt comments and docs

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

@@ -1,6 +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 feed here yet · 17 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).