Write a macro to generate namespaced Ids

[gterzian]

We have a bunch of Indexes and Ids in components/msg/constellation_msg.rs, see for example the BrowsingContextIndex and BrowsingContextId

servo/components/msg/constellation_msg.rs

Line 263 in 1b4162a

pub struct BrowsingContextIndex(pub NonZeroU32);

I find myself manually adding new ones regurlarly by hand, perhaps someone wants to write a macro for this? See for example the changes to this file: https://github.com/servo/servo/pull/26317/files#diff-8dc9268416cd4f037d50206e76c73cf9

I'd be great if we could just do something along the lines of namespaced_id!(ServiceWorkerId).

Note that each also require implementing a method on PipelineNamespace, which I guess will have to be done by hand(unless someone has a better idea).

I don't have much, if any, experience writing macros, but I'll venture ahead with a "less easy" label...

[AbhishekSharma102]

Hey @gterzian, I am new to rust and would like to work on this. Please let me know if no one else is working on this.

[gterzian]

It's not assigned to anyone, so you can do it if you like!