markdown.kak: Do not use regions for single/double ` spans
markdown.kak: Do not use regions for single/double ` spans

Using a region for them breaks any other regex based highlighter
we would want to apply on top of them.

Fixes #1870

Somasis/kakoune,casimir/kakoune,danr/kakoune,alexherbo2/kakoune,casimir/kakoune,alexherbo2/kakoune,casimir/kakoune,mawww/kakoune,occivink/kakoune,Somasis/kakoune,occivink/kakoune,jjthrash/kakoune,mawww/kakoune,jkonecny12/kakoune,jjthrash/kakoune,danr/kakoune,alexherbo2/kakoune,occivink/kakoune,jkonecny12/kakoune,lenormf/kakoune,danr/kakoune,jkonecny12/kakoune,Somasis/kakoune,lenormf/kakoune,lenormf/kakoune,occivink/kakoune,mawww/kakoune,mawww/kakoune,casimir/kakoune,Somasis/kakoune,danr/kakoune,jjthrash/kakoune,lenormf/kakoune,alexherbo2/kakoune,jjthrash/kakoune,jkonecny12/kakoune