Auto merge of #72717 - poliorcetics:try-from-int-to-nzint, r=dtolnay

Auto merge of #72717 - poliorcetics:try-from-int-to-nzint, r=dtolnay

Add TryFrom<{int}> for NonZero{int}

Adds `TryFrom<{int}> for NonZero{int}`.

It uses the existing `NonZero{int}::new()` and `Option::ok_or()` functions, meaning the checks are not repeated.

I also added tests, I tried to follow the convention I saw in the test file.

I also used `#[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")]`, but I have no idea if the feature/version are correctly named or even correct.