Fix missing include in json_ui.cc
Fix missing include in json_ui.cc

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