Rust Engine: refactor names, change tuples representation

[W95Psp]

This PR introduces two major changes:

• Enforces a strong abstraction over global identifiers:
  • The internal structure of identifiers is now fully hidden, improving encapsulation and simplifying usage.
• Changes the representation of tuples:
  • Tuples were previously treated as regular names. Tuples are the only "parametric" identifiers: there exists an infinity of tuple identifiers. Thus, destructuring identifiers as tuples identifier was not possible without hacks.
  • They are now explicitly represented using GlobalIdInner::Tuple, which is very simple to pattern match on.

How to review

Skip the code regeneration commits

[jschneider-bensch]

This might be really basic, but I need to understand more about the different Id types. I believe none of them are new to the Rust engine, but have been ported from the OCaml engine, right? Is there some documentation in the OCaml engine (or elsewhere) for GlobalId, ConcreteId, DefId, ExplicitDefId and LocalId?

[W95Psp]

Thanks for your review!
No, that makes sense, the hierachy of identifier types is a big overwhelming 😅

Some are similar to the OCaml engine, but it was mostly redesigned.

I added contents in the module doc of identifiers and global_id, does that help?

[maximebuyse]

I added a small comment, otherwise looks good!

[jschneider-bensch]

I added contents in the module doc of identifiers and global_id, does that help?

Thanks, that really helps me understand what's happening!

[jschneider-bensch]

I think it looks good, thanks for adding more documentation!

[W95Psp]

This PR is now reviewed, I'm now waiting for #1689.
When it is reviewed as well, I will rebase that PR.

[W95Psp]

I'm merge that branch in its parent branch