Closure formatting in diagnostics can be a bit verbose

Consider inputs like https://github.com/rust-lang/rust/blob/278a90913daf7707791020a592d722dd7971f196/tests/ui/closures/closure-clone-requires-captured-clone.rs#L1, the diagnostics is:

https://github.com/rust-lang/rust/blob/278a90913daf7707791020a592d722dd7971f196/tests/ui/closures/closure-clone-requires-captured-clone.stderr#L1-L8

The message mentioning the closure uses a format like

 LL |     let closure = move || { 
    |                   ------- within this `{closure@$DIR/closure-clone-requires-captured-clone.rs:13:19: 13:26}` 

which feels quite verbose. I guess the span [lo, hi) (in terms of (start, end) line/col) and file path do make it clear which closure is being referred to when there are multiple closures. So not a priority, just tracking this in case there's ways to perhaps make this a bit more concise without losing info -- or assess if that info is actually fully needed).

Start with tests/ui/closures/closure-clone-requires-captured-clone.rs and its corresponding .stderr output to understand the verbose closure location text. Trace where this diagnostic formatting is produced, then determine whether a shorter format can preserve enough location information; done means the intended wording is agreed and the UI output reflects it.