[Annotations] Support nested (static) classes

[Andre601]

From my own testing have I figured out that nested classes don't seem to be supported for creating a command using annotations.

As an example, assume the following class and annotation setup:

@Command("foo")
public class Foo{
    
    @Command("bar")
    public void bar(MyCommandSender sender){
        sender.message("Lorem Ipsum");
    }
    
    @Command("baz")
    public static class Baz{
        
        @Command("bar")
        public void bar(MyCommandSender sender){
            sender.message("Lorem Ipsum Dolor");
        }
    }
}

One might expect this to create the command structures /foo bar and /foo baz bar, but in actuality is it not registering the second command at all.

It would be great if nested classes could be supported, as this would allow a greater level of organization for the dev to use, as it would create a clearer structure in the end for longer command chains.