move to copy_as_gfm to behaviors since it is invoked on every page

app/assets/javascripts/copy_as_gfm.js → app/assets/javascripts/behaviors/copy_as_gfm.js

 /* eslint-disable class-methods-use-this, object-shorthand, no-unused-vars, no-use-before-define, no-new, max-len, no-restricted-syntax, guard-for-in, no-continue */
+
 import _ from 'underscore';
-import { insertText, getSelectedFragment, nodeMatchesSelector } from './lib/utils/common_utils';
-import { placeholderImage } from './lazy_loader';
+import { insertText, getSelectedFragment, nodeMatchesSelector } from '../lib/utils/common_utils';
+import { placeholderImage } from '../lazy_loader';
 
 const gfmRules = {
   // The filters referenced in lib/banzai/pipeline/gfm_pipeline.rb convert

app/assets/javascripts/behaviors/index.js

 import './autosize';
 import './bind_in_out';
+import './copy_as_gfm';
 import './details_behavior';
 import installGlEmojiElement from './gl_emoji';
 import './quick_submit';

app/assets/javascripts/main.js

@@ -46,7 +46,6 @@ import './commits';
 import './compare';
 import './compare_autocomplete';
 import './confirm_danger_modal';
-import './copy_as_gfm';
 import './copy_to_clipboard';
 import Flash, { removeFlashClickListener } from './flash';
 import './gl_dropdown';