Document that $kak_token_to_complete is zero-based, not 1-based.
Document that $kak_token_to_complete is zero-based, not 1-based.

Also, clean up some formatting: definition lists don't need a leading `-`, use
`$` for environment variables, consistent indentation, etc.

lenormf/kakoune,jkonecny12/kakoune,lenormf/kakoune,jkonecny12/kakoune,casimir/kakoune,alexherbo2/kakoune,mawww/kakoune,jkonecny12/kakoune,mawww/kakoune,alexherbo2/kakoune,casimir/kakoune,alexherbo2/kakoune,lenormf/kakoune,mawww/kakoune,alexherbo2/kakoune,mawww/kakoune,casimir/kakoune,casimir/kakoune,lenormf/kakoune,jkonecny12/kakoune