Horizontal acc (#595)

* accuracy means horizontal

* typo

---------

Co-authored-by: Bruce Wayne <harald.the.engineer@gmail.com>

log.capnp

@@ -269,8 +269,8 @@ struct GpsLocationData {
   # Represents heading in degrees.
   bearingDeg @5 :Float32;
 
-  # Represents expected accuracy in meters. (presumably 1 sigma?)
-  accuracy @6 :Float32;
+  # Represents expected horizontal accuracy in meters.
+  horizontalAccuracy @6 :Float32;
 
   unixTimestampMillis @7 :Int64;