Deprecation attribute: unique identifiers and module support

Motivation and Context

We want to be able to warn about deprecation of all the definitions inside a module. (E.g. Test for Test.Next).

Description

In this MR we add uniqueness identifiers to format strings (so it can start by @!UNIQ!). It will print a string only if the uniqueness string was never printed.

Then, a pass in Ast_typed will move the [@deprecated] attribute on a module to the values and irrefutable patterns inside (but only first-level).

Component

• compiler
• website
• webide
• vscode-plugin
• debugger

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Performance improvement (non-breaking change that improves performance)
• None (change with no changelog)

Changelog

Checklist:

• If a new syntax has been introduced, put a message on slack ligo-lsp
• Changes follow the existing coding style (use dune @fmt to check).
• Tests for the changes have been added (for bug fixes / feature).
• Documentation has been updated.
• Changelog description has been added (if appropriate).
• Start titles under ## Changelog section with #### (if appropriate).
• There is no image or uploaded file in changelog
• Examples in changed behaviour have been added to the changelog (for breaking change / feature).