Auto merge of #58180 - davidtwco:issue-58053, r=estebank

Fix span for closure return type when annotated.

Fixes #58053.

This PR adjusts the span used to label closure return types so that
if the user specifies the return type, i.e. `|_| -> X {}` instead of
`|_| {}`, we correctly highlight all of it and not just the last
character.

r? @pnkfelix

diff --cc src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs
Simple merge