Recognize canonical ? pattern with Result

[samueltardieu]

This recognizes the following expression as being equivalent to the question mark:

match x {
    Ok(v) => v,
    Err(e) => return Err(e.into()), // or `Into::into(x)` or `<T as Into<U>>::into(x)`
}

Fixes #15679

changelog: [question_mark]: recognizes a match with an early return with a call to .into() as possibly equivalent to a question mark

[rustbot]

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[Jarcho]

Thank you.

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