Auto merge of #77467 - jyn514:query-docs, r=oli-obk

Normalize `<X as Y>::T` for rustdoc

- Only run for `QPath::Resolved` with `Some` self parameter (`<X as Y>::T`)
- Fall back to the previous behavior if the path can't be resolved

The first commit is a pure refactor and should probably be reviewed by `@GuillaumeGomez.` I recommend reviewing the second commit on its own.

Fixes #77459.

r? `@eddyb`
cc `@danielhenrymantilla` , `@lcnr`

Author: bors