Detect invalid coordinates in selection_from_string
Detect invalid coordinates in selection_from_string

Fixes #1751

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