docs: Fix builder link from docs.rs #3345
docs: Fix builder link from docs.rs #3345

3468325b8d and afd0342a added extra context to the README's example.  However, when browsing it at docs.rs, the builder link just links back to the page you are own, offering little value.

Instead we'll now link to the tutorial which works as a next step from the example and resolves the "what do we link for the builder api" question.
clap-rs/clap,clap-rs/clap,clap-rs/clap