Auto merge of #107584 - matthiaskrgr:rollup-vav4ljz, r=matthiaskrgr

Rollup of 5 pull requests

Successful merges:

 - #107201 (Remove confusing 'while checking' note from opaque future type mismatches)
 - #107312 (Add Style Guide rules for let-else statements)
 - #107488 (Fix syntax in `-Zunpretty-expanded` output for derived `PartialEq`.)
 - #107531 (Inline CSS background images directly into the CSS)
 - #107576 (Add proc-macro boilerplate to crt-static test)

Failed merges:

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