IntoApp docs

[nipunn1313]

Please complete the following tasks

• I have searched the discussions
• I have searched the existing issues

Rust Version

rustc 1.58.0-nightly (b426445c6 2021-11-24)

Clap Version

3.0.6

Minimal reproducible code

Docs in https://docs.rs/clap/latest/clap/trait.IntoApp.html indicate that it's derived on Parser, Args, and Subcommand, but afaict it's only derived on Parser. Came across it while trying to figure out if it was possible to do MySubcommand::into_app().debug_assert()

Steps to reproduce the bug with the above code

It's a doc bug

Actual Behaviour

see above

Expected Behaviour

Docs should be consistent.

Additional Context

No response

Debug Output

No response

[epage]

Thanks for calling this out!