Could you make `@MustBeClosed` to have `ElementType.TYPE` in its `@Target`?

### Description of the problem / feature request:

Could you make `@MustBeClosed` to have `ElementType.TYPE` in its `@Target` and support it?

### Feature requests: what underlying problem are you trying to solve with this feature?

We have our own interface which must be closed when it's used. https://github.com/line/armeria/blob/master/core/src/main/java/com/linecorp/armeria/common/util/SafeCloseable.java
If we can annotate the class with the `@MustBeClosed`, we don't have to put the annotation all over the places where it's used.

### What version of Error Prone are you using?

2.4.0

### Have you found anything relevant by searching the web?

I couldn't. 😄