promql/functions.go
func funcSqrt(vals []Value, args Expressions, enh *EvalNodeHelper) Vector {
	return simpleFunc(vals, enh, math.Sqrt)
}
func funcSqrt(vals []Value, args Expressions, enh *EvalNodeHelper) Vector {
	return simpleFunc(vals, enh, math.Sqrt)
}
// === sqrt(Vector VectorNode) Vector ===