Added the formatting support

[Suyog241005]

Fixes

Fixes #25

Description

This PR implements auto-formatting (onDocumentFormatting) for JSON files using the existing jsonc-parser dependency.

Changes

• Registered documentFormattingProvider: true inside the server capabilities.
• Added a new Formatting feature module that maps the editor's formatting options (tabSize, insertSpaces) to jsonc.format.
• Added comprehensive unit tests for spaces, tabs, CRLF preservation, and invalid JSON error handling.

[Suyog241005]

Hey @jdesrosiers, opened the PR for the formatting support! Let me know if the changes look good to you.

[jdesrosiers]

Looks good so far. I left a few notes. Please also include onDocumentRangeFormatting.

There's also onDocumentOnTypeFormatting, but I think that's a separate concern. I'm not entirely sure what that one is for.

[Suyog241005]

Looks good so far. I left a few notes. Please also include onDocumentRangeFormatting.

There's also onDocumentOnTypeFormatting, but I think that's a separate concern. I'm not entirely sure what that one is for.

onDocumentOnTypeFormatting is used for formatting as you type (triggered by specific characters like ; or }), which is standard for programming languages but not necessary for JSON files since editors already handle JSON indentation naturally.

I will include onDocumentRangeFormatting as requested.

[srivastava-diya]

hey @Suyog241005 could you please have a look at why the tests are failing on windows. thanks!

[Suyog241005]

hey @Suyog241005 could you please have a look at why the tests are failing on windows. thanks!

Yeah, the tests were failing on Windows CI because I wasn't using EOL from node:os in the test file. I've updated the tests to use EOL so they are fully cross-platform now