types/ptr: deprecate ptr.To, use Go 1.26 new

Updates #18682

Change-Id: I62f6aa0de2a15ef8c1435032c6aa74a181c25f8f
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

types/views/views.go

@@ -19,7 +19,6 @@ import (
 	jsonv2 "github.com/go-json-experiment/json"
 	"github.com/go-json-experiment/json/jsontext"
 	"go4.org/mem"
-	"tailscale.com/types/ptr"
 )
 
 // ByteSlice is a read-only accessor for types that are backed by a []byte.
@@ -901,7 +900,7 @@ func (p ValuePointer[T]) Clone() *T {
 	if p.ж == nil {
 		return nil
 	}
-	return ptr.To(*p.ж)
+	return new(*p.ж)
 }
 
 // String implements [fmt.Stringer].