rc lisp: Fix variable highlighting
rc lisp: Fix variable highlighting

Fixes #2289

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