make sure PHP and Python reverse code does the same

The only allowable difference is precision of coordinates. Python uses
a precision of 7 digits where possible, which corresponds to the
precision of OSM data.

Also fixes some smaller bugs found by the BDD tests.

nominatim/server/falcon/server.py

@@ -10,7 +10,6 @@ Server implementation using the falcon webserver framework.
 from typing import Optional, Mapping, cast, Any
 from pathlib import Path
 
-import falcon
 from falcon.asgi import App, Request, Response
 
 from nominatim.api import NominatimAPIAsync
@@ -26,9 +25,12 @@ class HTTPNominatimError(Exception):
         self.content_type = content_type
 
 
-async def nominatim_error_handler(req: Request, resp: Response,
+async def nominatim_error_handler(req: Request, resp: Response, #pylint: disable=unused-argument
                                   exception: HTTPNominatimError,
                                   _: Any) -> None:
+    """ Special error handler that passes message and content type as
+        per exception info.
+    """
     resp.status = exception.status
     resp.text = exception.msg
     resp.content_type = exception.content_type

nominatim/server/sanic/server.py

@@ -36,7 +36,6 @@ class ParamWrapper(api_impl.ASGIAdaptor):
 
     def error(self, msg: str, status: int = 400) -> SanicException:
         exception = SanicException(msg, status_code=status)
-        exception.headers = {'content-type': self.content_type}
 
         return exception