convert uses of interface{} to any

Done via:
  find . -name "*.go" | xargs sed -i -E 's/interface\{\}/any/g'

PiperOrigin-RevId: 487033228

pkg/p9/p9test/p9test.go

@@ -87,7 +87,7 @@ func (m *Mock) RemoveChild(name string) {
 }
 
 // Matches implements gomock.Matcher.Matches.
-func (m *Mock) Matches(x interface{}) bool {
+func (m *Mock) Matches(x any) bool {
 	if om, ok := x.(*Mock); ok {
 		return m.QID.Path == om.QID.Path
 	}