cli, support subcommands

[podhmo]

from typing_extensions import Annotated
from egoist.go.types import Description

class greeting:
    """greeting subcommand"""

    def hello(self, *, name: str) -> None:
        from egoist.generators.clikit import runtime

        args = runtime.get_cli_options()
        args.name.help = "name of greeting target"

    def byebye(
        self, *, name: Annotated[str, Description("name of greeting target")]
    ) -> None:
        pass