Make #near_scope_options public for Rails 5.2

Rails 5.2 changed the receiver within a scope from `klass` to
`relation`. With that, we no longer have private access to
Geocoder::Store::ActiveRecord#near_scope_options, and so must make it
public.

see: https://github.com/rails/rails/pull/29301

lib/geocoder/stores/active_record.rb

@@ -87,8 +87,6 @@ module Geocoder::Store
         end
       end
 
-      private # ----------------------------------------------------------------
-
       ##
       # Get options hash suitable for passing to ActiveRecord.find to get
       # records within a radius (in kilometers) of the given point.
@@ -168,6 +166,8 @@ module Geocoder::Store
         }
       end
 
+      private # ----------------------------------------------------------------
+
       ##
       # SQL for calculating distance based on the current database's
       # capabilities (trig functions?).