Support trait constraints directly in a generics list

[jfecher]

Problem

Trait constraints currently may only be specified in a where clause. This is inconsistent with Rust which also supports it directly in a generics list.

Happy Case

Support trait constraints within a generics list.

fn foo<T: Bar>(x: T) { }

// same as
fn foo<T>(x: T) where T: Bar {}

Project Impact

None

Impact Context

No response

Workaround

None

Workaround Description

No response

Additional Context

No response

Would you like to submit a PR for this Issue?

None

Support Needs

No response