fix(overpass): read failure phrases from the remark, not element tags

overpassLooksRuntimeError and overpassLooksRateLimited searched the whole
200 body, element tags included. A result containing a place named
"Timed Out Escape Rooms" (or any tag with "runtime error", "out of
memory", "too many requests" or "rate_limited") was refused as an
upstream failure, and the endpoint was put on cooldown for every other
query.

Parse the body once. A data reply (one with an elements array) reports
failure in its remark, so the phrase checks run on the remark. Any other
body, an error page or JSON without elements, is matched whole as
before.

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+- 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.
+
 - Add Barcelona's bike share to the GBFS registry: Bicing (543 stations, the
   city's PBSC system) and AMBici (237 e-bike stations across the metropolitan
   area, run by nextbike). Both are keyless GBFS 2.3 feeds listed in