docs: fix errors reported by Vale 3.17.0

[dduugg]

What does this change do, and why?

The Documentation workflow installs Vale unpinned (brew install vale), and Vale 3.17.0 (published 2026-07-31T17:07Z) reports two docs/ errors that 3.16.0 did not. main last ran the job at 16:53Z on 2b7c468 and passed; every pull request built after 17:07Z fails the docs job on unchanged content, e.g. https://github.com/Homebrew/brew/actions/runs/30666983756/job/91276194089.

Both are genuine violations of our own styles rather than new false positives, so this fixes the prose instead of pinning the version:

• docs/Maintainer-Stipends-and-Grants.md:128 has an Oxford comma, which Homebrew.OxfordComma disallows.
• docs/index.md:48 links to How-To-Open-a-Homebrew-Pull-Request.md as "How to Open a Pull Request". Homebrew.Terms exempts only the exact phrase "How to Open a Homebrew Pull Request", and that is how every other page links to it (Adding-Software-to-Homebrew.md, Formula-Cookbook.md, Updating-Software-in-Homebrew.md). index.md was the lone outlier, so adding the missing "Homebrew" fixes the error and makes the link text consistent.

Step-by-step reproduction

$ brew install vale   # 3.17.0
$ vale docs/
 docs/Maintainer-Stipends-and-Grants.md
 128:3  error  No Oxford commas!  Homebrew.OxfordComma

 docs/index.md
 48:18  error  Use 'pull request' instead of 'Pull Request'.  Homebrew.Terms

✖ 2 errors, 0 warnings and 0 suggestions in 88 files.

With this change, vale docs/ reports 0 errors, 0 warnings and 0 suggestions in 88 files.

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• Have you followed our Contributing guidelines?
• Have you checked for other open Pull Requests for the same change?
• Have you explained what your changes do? Performance claims (e.g. "this is faster") must include Hyperfine benchmarks.
• Have you explained why you'd like these changes included, not just what they do?
• For bug fixes, have you given step-by-step brew commands to reproduce the bug?
• Have you written new tests (excluding integration tests)? Here's an example.
• Have you successfully run brew lgtm (style, typechecking and tests) locally?

Documentation prose only, so there is nothing for the last two boxes to cover: no Ruby changes for brew lgtm to check and no behaviour to test. Verified with vale docs/ on 3.17.0 instead, before and after.

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• I did not use AI/LLM to create this PR, or I disclosed the tool/model below and reviewed its output; I did not attribute commits to AI and will answer maintainer questions and review comments myself without AI/LLM.

AI was used. Claude Code (Claude Sonnet) traced the docs job failure on #23386 to the Vale 3.17.0 release, confirmed the two flagged lines are unchanged on main and are real style violations rather than regressions, checked that no open pull request already fixes them, and wrote this change. Verification: installed Vale 3.17.0 locally and ran vale docs/ on main to reproduce the two errors, then again with the fix to confirm 0 errors across the same 88 files.

[Copilot]

🟢 Ready to approve

The changes are minimal, documentation-only, and directly address the reported Vale style violations without introducing new content or behavioral risk.

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Pull request overview

Updates Homebrew’s documentation prose to comply with the repository’s Vale-enforced style rules after Vale 3.17.0 began flagging previously-unreported violations in docs/.

Changes:

• Removes an Oxford comma in docs/Maintainer-Stipends-and-Grants.md to satisfy Homebrew.OxfordComma.
• Updates the docs/index.md link text to match the standard phrasing “How to Open a Homebrew Pull Request …”, satisfying Homebrew.Terms and aligning with other docs pages.

File summaries

File	Description
docs/Maintainer-Stipends-and-Grants.md	Removes an Oxford comma in a conference travel reimbursement bullet list item.
docs/index.md	Adjusts link text to the canonical “How to Open a Homebrew Pull Request …” phrasing used elsewhere.

Review details

• Files reviewed: 2/2 changed files
• Comments generated: 0
• Review effort level: Lite

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[MikeMcQuaid]

Thanks!