Implement partial equivalence and extend forc migrate tool

[ironcev]

Description

This PR:

• implements partial equivalence in the core::ops, as explained in detail in Partial equivalence #6883. The implementation is opt-in and behind the partial_eq experimental feature flag.
• implements forc migrate migration steps for automatic migration to partial_eq feature.
• extends the infrastructure for writing forc migrate migrations.
• preserves Annotations on LexedModules in the LexedProgram. (Those were before stripped off and not available in the compiled Programs. This resulted in loss off //! doc-comments that are represented as doc-comment annotations.)

Extensions in the forc migrate infrastructure include:

• possibility to postpone migration steps. This allows writing multi-step migrations where the first step is usually early adopting an experimental feature by using cfg attributes in code. This possibility is crucial for migrating our own codebase where we want to early-adopt and test and stabilize experimental features.
• possibility to match elements on both mutable and immutable parsed trees. The initial assumption that immutable matching on typed trees will always be sufficient does not hold. Experimental cfg attributes can remove parts of typed trees that might be needed in analysis.
• LexedLocate(As)Annotated for easier location and retrieval of Annotated elements.
• additional implementations of existing traits.
• additional Modifiers for modifying existing elements in the lexed tree.
• New struct for convenient creation of often needed lexed tree elements. Note that we do not expect migrations to generate large new parts of lexed trees, but mostly to modify or copy and modify existing ones.

Almost all of the changes in the Sway files are done automatically by the migration steps. The only manual change was in the core library (std library is also automatically migrated) and in slight extension of two of the tests.

Note that some of the tests have Eq traits in trait constraints. As explained in the #6883, it is not necessary to change those to PartialEq. We might consider changing some of them, for testing purposes, and such a change is done on one of the tests that was testing the behavior of the Eq trait. But for the majority of the tests, there is no strict need for switching from Eq to PartialEq.

Rolling PartialEq out in the tests provoked three existing issues that will be fixed in separate PRs: #6897, #6898, #6899.

Checklist

• I have linked to any relevant issues.
• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation where relevant (API docs, the reference, and the Sway book).
  • If my change requires substantial documentation changes, I have requested support from the DevRel team
• I have added tests that prove my fix is effective or that my feature works.
• I have added (or requested a maintainer to add) the necessary Breaking* or New Feature labels where relevant.
• I have done my best to ensure that my PR adheres to the Fuel Labs Code Review Standards.
• I have requested a review from the relevant team or maintainers.

[codspeed-hq]

CodSpeed Performance Report

Merging #6900 will not alter performance

_{Comparing ironcev/partial-equivalence (307375e) with master (70c84ca)}

Summary

✅ 22 untouched benchmarks