Adjust README section for serializers to show full namespace of built…

…-in modules [ci skip]

lib/paper_trail/has_paper_trail.rb

@@ -115,7 +115,8 @@ def serialize_attributes_for_paper_trail(attributes)
 
         serialized_attributes.each do |key, coder|
           if attributes.key?(key)
-            coder = PaperTrail.serializer unless coder.respond_to?(:dump) # Fall back to current serializer if `coder` has no `dump` method
+            # Fall back to current serializer if `coder` has no `dump` method
+            coder = PaperTrail.serializer unless coder.respond_to?(:dump)
             attributes[key] = coder.dump(attributes[key])
           end
         end
@@ -140,7 +141,8 @@ def serialize_attribute_changes(changes)
 
         serialized_attributes.each do |key, coder|
           if changes.key?(key)
-            coder = PaperTrail.serializer unless coder.respond_to?(:dump) # Fall back to current serializer if `coder` has no `dump` method
+            # Fall back to current serializer if `coder` has no `dump` method
+            coder = PaperTrail.serializer unless coder.respond_to?(:dump)
             old_value, new_value = changes[key]
             changes[key] = [coder.dump(old_value),
                             coder.dump(new_value)]