Use fork suggestion helper in blob view

app/views/projects/_fork_suggestion.html.haml

-- if current_user
-  .js-file-fork-suggestion-section.file-fork-suggestion.hidden
-    %span.file-fork-suggestion-note
-      You're not allowed to
-      %span.js-file-fork-suggestion-section-action
-        edit
-      files in this project directly. Please fork this project,
-      make your changes there, and submit a merge request.
-    = link_to 'Fork', nil, method: :post, class: 'js-fork-suggestion-button gl-button btn btn-grouped btn-inverted btn-success'
-    %button.js-cancel-fork-suggestion-button.gl-button.btn.btn-grouped{ type: 'button' }
-      Cancel
+.js-file-fork-suggestion-section.file-fork-suggestion.hidden
+  %span.file-fork-suggestion-note
+    You're not allowed to
+    %span.js-file-fork-suggestion-section-action
+      edit
+    files in this project directly. Please fork this project,
+    make your changes there, and submit a merge request.
+  = link_to 'Fork', nil, method: :post, class: 'js-fork-suggestion-button gl-button btn btn-grouped btn-inverted btn-success'
+  %button.js-cancel-fork-suggestion-button.gl-button.btn.btn-grouped{ type: 'button' }
+    Cancel

app/views/projects/blob/_header.html.haml

@@ -20,5 +20,5 @@
       = download_blob_button(blob)
       = view_on_environment_button(@commit.sha, @path, @environment) if @environment
 
-= render 'projects/fork_suggestion'
+= render_fork_suggestion
 = render_if_exists 'projects/blob/header_file_locks', project: @project, path: @path