import { args } from "https://deno.land/x/feomasto@v0.1.0/priv/deps.ts";
const { SubCommand } = args;
Declare add subcommand to existing command parser
type
<Main extends CommandReturn<any, any, any>, Name extends string, Sub extends CommandReturn<any, any, any>, ErrList extends readonly ParseError[]>() => Command<SubCommandReturn<Main, Name, Sub>, ErrList>