promql/functions.go
func funcCeil(vals []Value, args Expressions, enh *EvalNodeHelper) Vector {
	return simpleFunc(vals, enh, math.Ceil)
}
func funcCeil(vals []Value, args Expressions, enh *EvalNodeHelper) Vector {
	return simpleFunc(vals, enh, math.Ceil)
}
// === ceil(Vector ValueTypeVector) Vector ===