feat: Run comptime code from annotations on a type definition

[jfecher]

Description

Problem*

Resolves #5255

Summary*

Implements the ability to run comptime code when an annotation is put on a type definition. This annotation must resolve to a comptime function in scope, which is then called with the type definition as an argument. There are currently no API functions to actually do anything with a TypeDefinition object. The plan is to add functions in the future to inspect or add fields & generics.

#[print_type]
struct Foo {
    bar: Field,
}

comptime fn print_type(typ: TypeDefinition) {
    println("hello from print_type_name at compile-time");
    println(typ); // only prints "(type definition)" currently
}

fn main(){}

Additional Context

Documentation*

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.