* [Diagnostics] Improve {{none}} fix-it verifier
* split two conditions
* define "none" constant
* support plural
* use Twine and add comment for replacement range
* check if {{none}} is at the end
* use noneMarkerStartLoc
* update second {{none}} error message
Co-Authored-By: Owen Voorhees <owenvoorhees@gmail.com>
* update test case for second {{none}}
* fix test case for new {{none}} check
* Use named struct
* set const
Co-authored-by: Owen Voorhees <owenvoorhees@gmail.com>
