Make it easy to add notes without the need to click a button.
(Note: Remember to edit @match to your own Redmine instance in the script!)
Add a note directly at the bottom of the issue page without the need of clicking the "edit" link.
Client-side implementation of Feature #3143: Add an 'Add Note' function to issue, to avoid optimistic-lock of issue' update when user just want to add a note.
Validated on redmine.org and Redmine 6.0.2.
