Auto merge of #7227 - tafia:tafia-mime_classifier, r=jdm
Auto merge of #7227 - tafia:tafia-mime_classifier, r=jdm

rewrite of mime_classifier.rs to use more iterators

Rewrite few parts of the file to use more iterators.

Note that I have **no idea** what the code is actually doing functionally, I just tried to mimic exactly what was being done. All tests are ok

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