refine usage docs of `store` in combination with `hstore` and `json`.

refs #11561 #12700

activerecord/lib/active_record/store.rb

@@ -15,9 +15,9 @@ module ActiveRecord
   # You can set custom coder to encode/decode your serialized attributes to/from different formats.
   # JSON, YAML, Marshal are supported out of the box. Generally it can be any wrapper that provides +load+ and +dump+.
   #
-  # With PostgreSQL, the +store+ feature is not supported for field types such as Hstore
-  # or JSON because it would add an extra layer of serialization and this is not needed. 
-  # Rely on +store_accessor+ instead.
+  # NOTE - If you are using special PostgreSQL columns like +hstore+ or +json+ there is no need for
+  # the serialization provieded by +store+. You can simply use +store_accessor+ instead to generate
+  # the accessor methods.
   #
   # Examples:
   #