Auto merge of #8382 - tamaroning:suggest_iter_instead_of_into_iter, r=giraffate

Auto merge of #8382 - tamaroning:suggest_iter_instead_of_into_iter, r=giraffate

[explicit_counter_loop] suggests `.into_iter()`, despite that triggering [into_iter_on_ref] in some cases

I have modified `fn make_iterator_snippet` in clippy_lints/src/loops/utils.rs ,so this change has some little influence on another lint [manual_flatten] .

fixes #8155

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changelog: Fix that [`explicit_counter_loop`] suggests `into_iter()` despite that triggering [`into_iter_on_ref`] in some cases