docs: update hooks.md event name list and count to include sessionEnd and userPromptSubmitted

[PratikWayase]

Description

This PR updates the "Manifest Schema and Validation" section in docs/contributing/hooks.md to accurately reflect the allowed hook event names defined in the JSON schema.

The schema (scripts/linting/schemas/hook-manifest.schema.json) defines ten allowed event names, but the documentation previously stated there were "eight" and missed two in the inline enumeration. This PR updates the count from "eight" to "ten" and adds sessionEnd and userPromptSubmitted to the list so the documentation perfectly matches the schema's propertyNames.enum.

Related Issue(s)

Fixes #2498

Type of Change

Select all that apply:

Code & Documentation:

• Bug fix (non-breaking change fixing an issue)
• New feature (non-breaking change adding functionality)
• Breaking change (fix or feature causing existing functionality to change)
• Documentation update

Infrastructure & Configuration:

• GitHub Actions workflow
• Linting configuration (markdown, PowerShell, etc.)
• Security configuration
• DevContainer configuration
• Dependency update

AI Artifacts:

• Reviewed contribution with hve-builder and addressed all actionable findings
• Copilot instructions (.github/instructions/*.instructions.md)
• Copilot prompt (.github/prompts/*.prompt.md)
• Copilot agent (.github/agents/*.agent.md)
• Copilot skill (.github/skills/*/SKILL.md)
• Copilot hook (.github/hooks/*/*.json)
• Eval spec added/updated for changed AI artifacts (evals/)

Other:

• Script/automation (.ps1, .sh, .py)
• Other (please describe):

Testing

• Cross-referenced the updated list of 10 events against the propertyNames.enum array in scripts/linting/schemas/hook-manifest.schema.json to ensure a 1:1 match.
• Ran npm run lint:hooks locally to ensure no manifest validation regressions (Passed successfully).
• Previewed the markdown file in VS Code to ensure correct rendering of inline code blocks and formatting.

Checklist

Required Checks

• Documentation is updated (if applicable)
• Files follow existing naming conventions
• Changes are backwards compatible (if applicable)
• Tests added for new functionality (if applicable)

AI Artifact Contributions

(Not applicable for this documentation-only fix)

Required Local Checks

• Local validation aggregate: npm run validate:local
• Documentation validation (if docs changed): npm run validate:docs
• Spell checking: npm run spell-check
• Link validation: npm run lint:md-links

Security Considerations

• This PR does not contain any sensitive or NDA information
• Any new dependencies have been reviewed for security issues
• Security-related scripts follow the principle of least privilege

Additional Notes

This was a simple documentation mismatch introduced in PR #2478 where the schema and compatibility sections were updated, but the introductory enumeration and count were missed. No code or schema changes were required for this fix.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.73%. Comparing base (ec2b194) to head (ae26904).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2549      +/-   ##
==========================================
- Coverage   82.75%   82.73%   -0.03%     
==========================================
  Files         155      155              
  Lines       20963    20943      -20     
  Branches       13       13              
==========================================
- Hits        17348    17327      -21     
- Misses       3613     3614       +1     
  Partials        2        2              

Flag	Coverage Δ
docusaurus	94.44% <ø> (ø)
pester	86.19% <ø> (-0.02%)	⬇️

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see 4 files with indirect coverage changes

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