extension_api: Expose hard_tabs in LanguageSettings

[tsinis]

Closes #21822
The issue is closed already, but it was requested to provide the hard_tabs boolean param.

Follow-up to #52175
Reviewed by @maxdeviant (it already bumped the settings path to v0.8.0, so this hard_tabs change only needs 2 files, 2-3 lines of code additions).

Context

Exposes hard_tabs from AllLanguageSettings to the Extension
API's LanguageSettings struct. Currently, only tab_size and preferred_line_length are available to extensions, which prevents language extensions (e.g., Go, C++) from reading the user's hard tabs preference and forwarding it to their language server or formatter (e.g., as rustfmt.hard_tabs or clang-format.UseTab).

Related: #21822 (comment)

How to Review

Small change — follow how tab_size is plumbed through:

1. WIT definition (language-settings record)
2. extension_api Rust struct
3. Host-side bridge conversion

The new field follows the exact same pattern.

Self-Review Checklist

• I've reviewed my own diff for quality, security, and reliability
• Unsafe blocks (if any) have justifying comments
• The content is consistent with the UI/UX checklist
• Tests cover the new/changed behavior
  • Compile-time verified via WIT bindings; no runtime behavior change
• Performance impact has been considered and is acceptable

Release Notes:

• N/A

[zed-industries-bot]

	Messages
📖	This PR includes links to the following GitHub Issues: #21822 If this PR aims to close an issue, please include a Closes #ISSUE line at the top of the PR body.

Generated by 🚫 dangerJS against f726499

[tomhoule]

The addition makes sense, and it should be safe. Thank you for the contribution!

[tsinis]

The addition makes sense, and it should be safe. Thank you for the contribution!

Thanks a lot for the review and approval, @tomhoule! I'm also wondering - where we can expect zed_extension_api crate update too (so we can reference it safely in Zed extensions)? Last bump was 10+ months ago 🤔 Danke!

[MrSubidubi]

We currently do not have a set date for the next bump, but it might very well be that it will still take some time, since there are other improvements to land and we currently do not have a large enough improvement in the API that would warrant a ship. We originally forked another version for agent provider extensions, but had to postpone these for the time being. Sorry and Gruß!