Extend while_let_loop to warn even if there are statements after match

[Zarathustra30]

The implementation of while_let_loop is incomplete. In cases when additional statements follow the match, such as the following:

loop {
    let bi = match bodies.next() {
        Some(bi) => bi,
        None => break
    };
    additional_statement1(bi);
    additional_statement2();
}

the loop can still be replaced with while let

while let Some(bi) = bodies.next() {
    additional_statement1(bi);
    additional_statement2();
}

These snippets are slightly different in theory, but identical in practice.

[llogiq]

Good catch!