Auto merge of #7502 - flip1995:rollup-y3ho3w0, r=flip1995

Rollup of 3 pull requests

Successful merges:

 - #7279 (Adapting the lint list to Clippy's new metadata format)
 - #7298 (Switch CI to new metadata collection)
 - #7420 (Update lint documentation to use markdown headlines)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

changelog: rollup