Make sure spans on non_camel_case_types are correct

[brson]

I think they are pretty sloppy right now, pointing to the item instead of the ident

[brson]

This can't be done without adding spans to idents, which is a sizable task.

[eholk]

This is probably an easier task after @paulstansifer's work on interning all the idents.

[catamorphism]

Seems... non-critical. De-milestoning.

[emberian]

@brson given the following test cases:

struct barz_type {
    a: uint,
    b: uint
}

fn main() {
    let x: barz_type = barz_type {a: 5};
}

and

fn main() {
    let x= barz_type {a: 5};
}

the spans are correct. Closing.