[with_annotated] Using `ArgumentBlock` does not works with groups

[neoniobium]

Description

ArgumentBlock typed arguments used with with_annotated do not work well with argument groups.

@dataclass
class Block(ArgumentBlock):
    A: ...
    B: ...


class App(Cmd):
    @with_annotated(groups=(Group("Block", ...), ...))
    def do_with_block(self, block_argument: Block) -> None:
        ...

Expected Behavior

The argument group should be created, and all arguments defined in Block should be listed in it (see the help message).

Actual Behavior

An argument group is created, but it does not list any arguments. Defining Group("A", "B", ...) is rejected and causes an error.

Possible Solution

I see at least three possible approaches:

1. List all arguments defined in the ArgumentBlock in the corresponding argument groups when using the block to create the group.
2. Allow arguments defined in the ArgumentBlock to be referenced when defining argument groups.
3. Add syntax to define default argument groups inside the ArgumentBlock.