Add traits in Rust highlights (#10731)

Question: I use type.super here because I made a similar change to the
ruby syntax to apply the same style to superclasses.
With this in mind, should this change be renamed to type.trait or should
it be renamed to something like type.italic so the ruby syntax or any
other language can all use type.italic? or maybe something else
altogether.

<img width="597" alt="image"
src="https://github.com/zed-industries/zed/assets/7274458/9d02dba0-75a4-4439-9f31-fd8aa0873075">

Release Notes:

- Exposed Rust traits as `type.interface` for individual syntax theming.

crates/languages/src/rust/highlights.scm

@@ -3,6 +3,12 @@
 (self) @variable.special
 (field_identifier) @property
 
+(trait_item name: (type_identifier) @type.interface)
+(impl_item trait: (type_identifier) @type.interface)
+(abstract_type trait: (type_identifier) @type.interface)
+(dynamic_type trait: (type_identifier) @type.interface)
+(trait_bounds (type_identifier) @type.interface)
+
 (call_expression
   function: [
     (identifier) @function