Auto merge of #125257 - jieyouxu:rollup-11evnm9, r=jieyouxu

Rollup of 3 pull requests

Successful merges:

 - #125214 (Only make GAT ambiguous in `match_projection_projections` considering shallow resolvability)
 - #125236 (Add tests for `-Zunpretty=expanded` ported from stringify's tests)
 - #125251 (Clarify how String::leak and into_boxed_str differ )

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

Author: bors