Address Ameba issues

spec/spectator/mocks/reference_mock_registry_spec.cr

@@ -35,7 +35,7 @@ Spectator.describe Spectator::ReferenceMockRegistry do
       obj1 = "foo"
       obj2 = "bar"
       registry[obj2] << Spectator::ValueStub.new(:obj2, 42)
-      expect { registry.fetch(obj2) { no_stubs } }.to_not change { registry[obj2] }
+      expect { registry.fetch(obj1) { no_stubs } }.to_not change { registry[obj2] }
     end
   end
 end

src/spectator/mocks/stubbable.cr

@@ -195,7 +195,7 @@ module Spectator
 
         {% original = "previous_def#{" { |*_spectator_yargs| yield *_spectator_yargs }".id if method.accepts_block?}".id %}
       {% end %}
- 
+
       {% # Reconstruct the method signature.
 # I wish there was a better way of doing this, but there isn't (at least not that I'm aware of).
 # This chunk of code must reconstruct the method signature exactly as it was originally.