Update crate_name to use the attribute template

[ehuss]

New rules:

• ❗ crate.crate_name.syntax
• ❗ crate.crate_name.allowed-positions
• ❗ crate.crate_name.duplicates

Renamed rules:

• crate.crate_name.general is now crate.crate_name.intro
• crate.crate_name.restriction is now crate.crate_name.required-format

[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.