Rollup merge of #108557 - Nathan-Fenner:nathanf/adjust-error-span-fix-Some, r=WaffleLapkin

Point error span at Some constructor argument when trait resolution fails

This is a follow up to #108254 and #106477 which extends error span refinement to handle a case which I mistakenly believed was handled in #106477. The goal is to refine the error span depicted below:

```rs
trait Fancy {}
impl <T> Fancy for Option<T> where T: Iterator {}

fn want_fancy<F>(f: F) where F: Fancy {}

fn example() {
    want_fancy(Some(5));
//  (BEFORE)   ^^^^^^^ `{integer}` is not an iterator
//  (AFTER)         ^  `{integer}` is not an iterator
}
```

I had used a (slightly more complex) example as an illustrative example in #108254 , but hadn't actually turned it into a test, because I had (incorrectly) believed at the time it was covered by existing behavior. It turns out that `Some` is slightly "special" in that it resolves differently from the other `enum` constructors I had tried, and therefore this test was actually broken.

I've now updated the tests to include this example, and fixed the code to correctly resolve the `Some` constructor so that the span of the error is reduced.

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