bug#69625: 30.0.50; [PATCH] rust-ts-mode doesn't fontify some enum

[Yuan Fu]

X-Debug-CC: dev@rjt.dev <mailto:dev@rjt.dev>

(I lied a little bit about on the [PATCH] part: I have a solution but didn’t 
turn it into a patch yet.)

The problem is follows: given the rust code below, some enum are not fontified 
with type face under font lock level 3, and those enum are fontified as 
function or variable under font lock level 4.

fn main() {
    func(MyEnum::VariantA(0));
    func(MyEnum::VariantB);
    func(VariantC);
    func(VariantD(0));
}

VariantA and VariantB are fontified correctly, but VariantC and VariantD are 
not.

I think a simple rule that fontifies every capitalized identifier would fix 
this. But I don’t know if that’ll create other problem. AFAIK capitalized 
identifier is always some type in rust, right?

This is first reported on rust-mode’s GitHub repo: 
https://github.com/rust-lang/rust-mode/issues/518

Yuan