Objective

• Fixes Test run gutter marker appear inside markdown code blocks but do nothing when clicked #50781

Solution

• Added a new runnable config to LanguageConfig that disables runnables if set to false
• Changed config.toml config for Markdown to disable runnables

Testing

• Added tests to check that the runnables configuration is enforced
• Added tets to check that the default runnable configuration (true) is set, meaning, languages by default do load runnables to not change current behavior
• This changes can be checked by opening a demo file like the one on the linked issue, and opening a language file (.go, .rs) with tests to check that runnables are still being displayed on the editor.

Self-Review Checklist:

• I've reviewed my own diff for quality, security, and reliability
• Unsafe blocks (if any) have justifying comments
• The content adheres to Zed's UI standards (UX/UI and icon guidelines)
• Tests cover the new/changed behavior
• Performance impact has been considered and is acceptable

Showcase

Left is markdown with language config runnable = false and right is latest zed nightly release.

Release Notes:

• Added runnable option to disable runnables via language configuration.
• Fixed runnables showing up on markdown code fences