Mark inputs for notes with GFM capabilities

app/views/notes/_common_form.html.haml

@@ -8,7 +8,7 @@
 
     = f.hidden_field :noteable_id
     = f.hidden_field :noteable_type
-    = f.text_area :note, size: 255, class: 'note-text'
+    = f.text_area :note, size: 255, class: 'note-text gfm-input'
     #preview-note.preview_note.hide
     .hint
       .right Comments are parsed with #{link_to "GitLab Flavored Markdown", help_markdown_path, target: '_blank'}.

app/views/notes/_per_line_form.html.haml

@@ -13,7 +13,7 @@
             = f.hidden_field :noteable_id
             = f.hidden_field :noteable_type
             = f.hidden_field :line_code
-            = f.text_area :note,  size: 255, class: 'line-note-text'
+            = f.text_area :note,  size: 255, class: 'line-note-text gfm-input'
             .note_actions
               .buttons
                 = f.submit 'Add note', class: "btn save-btn submit_note submit_inline_note", id: "submit_note"