Fix lint error

spec/mailers/notify_spec.rb

@@ -2074,7 +2074,7 @@ RSpec.describe Notify do
       end
 
       it 'includes only one link to the highlighted_diff_email' do
-          expect(subject.html_part.body.raw_source).to include('assets/mailers/highlighted_diff_email').once
+        expect(subject.html_part.body.raw_source).to include('assets/mailers/highlighted_diff_email').once
       end
     end