Don't render the edit_form view for system notes

app/views/projects/notes/_note.html.haml

@@ -59,6 +59,8 @@
         .note-text
           = preserve do
             = markdown(note.note, {no_header_anchors: true})
+        - unless note.system?
+          -# System notes can't be edited
           = render 'projects/notes/edit_form', note: note
 
       - if note.attachment.url