@Retention(value=RUNTIME)
@Target(value={METHOD,TYPE})
public @interface Subcommand
Marks a method as a subcommand that has a parent. Subcommand methods
must have a Command annotation, either on the method
itself, or on the declaring class.
Subcommand annotations are also replaceable by Command ones, however
when Command is used, it should include the entire command path.
The subcommand name, and aliases if any. Values can contain spaces,
in which case it would automatically walk through the categories and
correctly calculate the command path.