rc fish: fix keyword highlighting false positive
rc fish: fix keyword highlighting false positive

"command" is a built-in, but these are not:

	$command
	some-command
	command-some

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