Add feature for referencing parent path in @DefaultFor with prefix

[bivashy]

This would help creating OrphanCommand with @DefaultFor annotation. We can easily reference like: \@DefaultFor("~"), and it would take parent path.

For example:

@Command("simple")
public class SimpleCommand {
    @DefaultFor("~")
    public void onCommand(){
        // executed when /simple dispatched 
    }

    @DefaultFor({"~", "test"}) // I think it will behavior like subcommand
    public void onTestCommand(){
       // executed when /simple test dispatched
    }

    @DefaultFor({"too","~"}) // Its like subcommand, but revesed
    public void onTooCommand(){
       // executed when /too simple dispatched
    }
}

And yes, like that command will be invalid and throw

@Command("simple")
public class SimpleCommand {
    @DefaultFor("~")
    public void onCommand(){
        // executed when /simple dispatched
    }

    @DefaultFor({"~", "test"}) // I think it will behavior like subcommand
    public void onTestCommand(){
        // executed when /simple test dispatched
    }

    @DefaultFor({"too","~"}) // Its like subcommand, but reversed
    public void onTooCommand(){
        // executed when /too simple dispatched
    }

    @DefaultFor("simple")
    public void onInvalidCommand(){
        // executed when /simple dispatched
    }
}

Exception:

Exception in thread "main" java.lang.IllegalArgumentException: Category 'simple' has more than one default action! (public void SimpleCommand.onCommand() and public void SimpleCommand.onInvalidCommand())
    at revxrsal.commands.core.CommandExecutable.parent(CommandExecutable.java:158)
    at revxrsal.commands.core.CommandParser.lambda$parse$4(CommandParser.java:177)
    at java.util.ArrayList.forEach(ArrayList.java:1259)
    at revxrsal.commands.core.CommandParser.parse(CommandParser.java:152)
    at revxrsal.commands.core.CommandParser.parse(CommandParser.java:106)
    at revxrsal.commands.core.BaseCommandHandler.register(BaseCommandHandler.java:188)