[#1645]Hover upgrade

Motivation and Context

Resolves #1645 (closed)

Description

go to definition works fine now in case of definition is in a module. All the corresponding requests consequently improved. hover result is pretty-printed now. Code of hover and go to type definition was refactored

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

Improves behavior of LSP requests in case of modules. Adds syntax highlighting to hover request. Adds support for hover over modules

Checklist:

• 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).