Fix malformed `suggestion` wording in PR review guidance

> [!CAUTION]
> Protected files were modified in this change.
> This pull request is in `request_review` mode and requires explicit human scrutiny before merge.
>
> Protected files: `README.md`

## Summary
- fix malformed inline formatting in the RWX PR review README
- fix malformed prompt text in RWX and RO PR review action constraints
- keep wording consistent as `suggestion` blocks across all three user-facing surfaces

## Validation
- ran: `make lint-actions`

Closes \#1863

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[What is this?](https://ela.st/github-ai-tools) | [From workflow: Trigger Text Auditor](https://github.com/elastic/ai-github-actions/actions/runs/32257405795)

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---

> [!NOTE]
> This was originally intended as a pull request, but the git push operation failed.
>
> **Original error:** pushSignedCommits: refusing unsigned push for branch 'fix-1863-suggestion-inline-format-ce722bc0b2d2e6de': Signed-commit payload violates file-protection policy (request_review): claude-workflows/pr-review/rwx/README.md
>
> **Workflow Run:** [View run details and download bundle artifact](https://github.com/elastic/ai-github-actions/actions/runs/32257405795)
>
> The bundle file is available in the `agent` artifact in the workflow run linked above.

To create a pull request with the changes:

```sh
# Download the artifact from the workflow run
gh run download 32257405795 -n agent -D /tmp/agent-32257405795

# Fetch the bundle into a temporary ref, then update the local branch
git fetch /tmp/agent-32257405795/aw-fix-1863-suggestion-inline-format.bundle refs/heads/fix-1863-suggestion-inline-format:refs/bundles/create-pr-fix-1863-suggestion-inline-format-ce722bc0b2d2e6de-13771aa9
git update-ref refs/heads/fix-1863-suggestion-inline-format-ce722bc0b2d2e6de refs/bundles/create-pr-fix-1863-suggestion-inline-format-ce722bc0b2d2e6de-13771aa9
git checkout fix-1863-suggestion-inline-format-ce722bc0b2d2e6de
# Ensure the working tree matches the updated branch
git reset --hard
# Remove the temporary bundle ref
git update-ref -d refs/bundles/create-pr-fix-1863-suggestion-inline-format-ce722bc0b2d2e6de-13771aa9

# Push the branch to origin
git push origin fix-1863-suggestion-inline-format-ce722bc0b2d2e6de

# Create the pull request
gh pr create --title 'Fix malformed `suggestion` wording in PR review guidance' --base main --head fix-1863-suggestion-inline-format-ce722bc0b2d2e6de --repo elastic/ai-github-actions
```

Start with claude-workflows/pr-review/rwx/README.md and search the RWX and RO PR review action constraints for the malformed `suggestion` wording. Run `make lint-actions`; done means the inline formatting and prompt text are consistent as `suggestion` blocks across all three user-facing surfaces.

Written by the indexing model from the issue text.