[regression] cargo doc -p clap doesn't provide useful docs

[zetok]

Clap version

clap v3.0.0-beta.2

Where

doc/clap/index.html
doc/clap/trait.Subcommand.html

What's wrong

The docs that were available with clap v2.33.3 are no longer there. At least for the stuff I wanted to check.

• Root of the crate no longer shows anything useful.
• Subcommand instead of useful docs only shows @TODO @release @docs.

How to fix

Put the documentation back in?

[pksunkara]

There's a doc feature flag you need to set and use nightly if you want to get the main intro doc locally.

And the @TODO means just that. Todo. Tracked in v3 release.