Add iterator reduction coverage to never_loop

[cuongleqq]

Fixes rust-lang/rust-clippy#16061.

Extend never_loop to also lint iterator reduction methods (e.g. for_each, try_for_each, fold, try_fold, reduce, all, any) when the closure’s body diverges (return type !). Add a UI test never_loop_iterator_reduction to cover these cases.

Testing:

• TESTNAME=never_loop_iterator_reduction cargo uitest

changelog: [never_loop]: lint diverging iterator reduction closures like for_each and fold