Naming the button to switch to the edit screen 'Edit' was a bad choice
since for draft comments there was already an 'Edit' button to edit the
draft comment. Having two 'Edit' buttons with different actions was
confusing.
In addition the 'Fix' button is moved to the end of the line to keep the
focus on the 'Reply' button, since the main purpose of the diff screen
is reviewing changes and commenting on them.
Change-Id: I09b928a46d5f4cfeb2dc715fe13fadb755801050
f549aa70c1