Rollup merge of #33351 - birkenfeld:loop-label-spans, r=pnkfelix

 This makes the \"shadowing labels\" warning *not* print the entire loop as a span, but only the lifetime.

Also makes #31719 go away, but does not fix its root cause (the span of the expanded loop is still wonky, but not used anymore).

diff --cc src/librustc_resolve/lib.rs
Simple merge

diff --cc src/libsyntax/ext/expand.rs
Simple merge