Fix "Replace match with if let" not to trigger when invalid transformations occur

[sgasho]

closes: #11373
closes: #19443

example:

match val {
    0 | 1 => {
        entry.remove();
    }
    v => *v -= 1,
}

before this PR
else clause never be executed (all val matches if clause)

if let v = val {
    *v -= 1
} else {
    entry.remove();
}

this PR
"Replace match with if let" not shown up.

An alternative proposal and my thoughts of it

Switching the order of "if" and "else" in the above example and replacing "v" with "val" could work like below.

if let 0 | 1 = val {
    entry.remove()
} else {
    *val -= 1
};

However, this idea requires more code, and it seems like over-engineering to me.

[ShoyuVanilla]

Thanks!