types/views: use slices.Contains{,Func}

Updates #8419

Change-Id: Ib1a9cb3fb425284b7e02684072a4e7a35975f35c
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

types/views/views.go

@@ -286,22 +286,12 @@ func (v Slice[T]) ContainsFunc(f func(T) bool) bool {
 //
 // As it runs in O(n) time, use with care.
 func SliceContains[T comparable](v Slice[T], e T) bool {
-	for _, x := range v.ж {
+	return slices.Contains(v.ж, e)
-		if x == e {
-			return true
-		}
-	}
-	return false
 }
 
 // SliceContainsFunc reports whether f reports true for any element in v.
 func SliceContainsFunc[T any](v Slice[T], f func(T) bool) bool {
-	for _, x := range v.ж {
+	return slices.ContainsFunc(v.ж, f)
-		if f(x) {
-			return true
-		}
-	}
-	return false
 }
 
 // SliceEqual is like the standard library's slices.Equal, but for two views.