Remove trailing ':' from racer execution
Remove trailing ':' from racer execution

When AWK processes the racer response, it adds a trailing ':' that
kakoune completion expects to lead to a row having an 'a|b|c' shape,
but it's empty instead. Removing the extra ':' allows the racer
complation to actually work.

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