Add documentation suggestion automation

[morgankrey]

Adds scripts and a GitHub Action workflow for automatically suggesting documentation updates when PRs modify user-facing code.

Scripts

• script/docs-suggest: Analyze PRs/commits for documentation needs using AI
• script/docs-suggest-publish: Create a PR from batched suggestions
• script/docs-strip-preview-callouts: Remove Preview callouts when shipping to stable
• script/test-docs-suggest-batch: Testing utility for batch analysis

Workflow

The GitHub Action (.github/workflows/docs_suggestions.yml) handles two scenarios:

1. PRs merged to main: Suggestions are batched to docs/suggestions-pending branch for the next Preview release
2. Cherry-picks to release branches: Suggestions are posted as PR comments for immediate review

Callout Types

The system distinguishes between:

• Additive features (new commands, settings, UI):

  > **Preview:** This feature is available in Zed Preview. It will be included in the next Stable release.

• Behavior modifications (changed defaults, altered existing behavior):

  > **Changed in Preview (v0.XXX).** See [release notes](/releases#0.XXX).

Both callout types are stripped by docs-strip-preview-callouts when features ship to stable.

Example Output

See PR #49190 for example documentation suggestions generated by running this on PRs from the v0.224 preview window.

Usage

# Analyze a PR (auto-detects batch vs immediate mode)
script/docs-suggest --pr 49100

# Dry run to see assembled context
script/docs-suggest --pr 49100 --dry-run

# Create PR from batched suggestions
script/docs-suggest-publish

# Strip callouts for stable release
script/docs-strip-preview-callouts

Release Notes:

• N/A