Disambiguate adt names

[Trzyq0712]

Addresses #155.

Problem

Using base names for types caused ConsistencyError collisions in the VIPER backend, notably for:

• Cross-module (or crate) collisions: e.g., std::ascii::EscapeDefault vs. std::char::EscapeDefault.
• Local shadowing: Multiple struct Bar definitions in different scopes of the same function.

Solution

1. Joining the crate name and all path segments with $$.
2. Appending the compiler's internal disambiguator (using $) when it is non-zero.
3. Explicitly handling anonymous namespaces and associated types to ensure local uniqueness.

Example Output:

• 0$$core$$ascii$$EscapeDefault
• 0$$main$$Bar vs. 0$$main$$Bar$1

[JonasAlaif]

I'm not such a big fan of this since it'll make the Viper program virtually unreadable (even more so than it already is), even for small programs. Any solution that does this would need to use the simple name if there is no conflict and the complex name otherwise. Alternatively, to be able to toggle this under a configuration flag.

Note that you could probably replace your implementation with rustc's debug formatting for DefId followed by a sanitize (to replace all the :: with Viper-valid stuff).