util/cache: fix missing interface methods (#11275)

Updates #cleanup


Change-Id: Ib3a33a7609530ef8c9f3f58fc607a61e8655c4b5

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>

util/cache/none.go

@@ -8,6 +8,8 @@ package cache
 // It is safe for concurrent use if the underlying FillFunc is.
 type None[K comparable, V any] struct{}
 
+var _ Cache[int, int] = None[int, int]{}
+
 // Get always calls the provided FillFunc and returns what it does.
 func (c None[K, V]) Get(_ K, f FillFunc[V]) (V, error) {
 	v, _, e := f()
@@ -15,4 +17,7 @@ func (c None[K, V]) Get(_ K, f FillFunc[V]) (V, error) {
 }
 
 // Forget implements Cache.
-func (c None[K, V]) Forget() {}
+func (None[K, V]) Forget(K) {}
+
+// Empty implements Cache.
+func (None[K, V]) Empty() {}