Rollup merge of #102871 - notriddle:notriddle/trait-impl-anchor, r=GuillaumeGomez

rustdoc: clean up overly complex `.trait-impl` CSS selectors

When added in 45964368f4a2e31c94e9bcf1cef933c087d21544, these multi-class selectors were present in the initial commit, but no reason was given why the shorter selector wouldn't work.

Author: matthiaskrgr