Create release notes for DevTools 2.60.0

[srawlins]

Presubmit checklist

• If you are unwilling, or unable, to sign the CLA, even for a tiny, one-word PR, please file an issue instead of a PR.
• If this PR is not meant to land until a future stable release, mark it as draft with an explanation.
• This PR follows the Google Developer Documentation Style Guidelines—for example, it doesn't use i.e. or e.g., and it avoids I and we (first-person pronouns).
• This PR uses semantic line breaks
  of 80 characters or fewer.

[gemini-code-assist]

Code Review

This pull request adds the release notes for DevTools version 2.60.0. The review feedback focuses on improving consistency and adherence to style guidelines across the document. Specifically, it suggests replacing abbreviations like "e.g." with "for example", ensuring consistent past-tense verb usage (such as "Resolved" and "validated"), standardizing bullet points to use asterisks instead of hyphens, formatting issue links consistently, and wrapping lines to respect the 80-character limit.

[flutter-website-bot]

Staged preview of the updated docs.flutter.dev site (updated for commit 7241758):

https://flutter-docs-prod--docs-pr13565-devtools-release-notes-4buruyfp.web.app

[flutter-website-bot]

Staged preview of the updated flutter.dev site (updated for commit 7241758):

https://flutter-dev-230821--www-pr13565-devtools-release-notes-bqpb7s99.web.app

[parlough]

Thanks! Looks good to me.