Add timeline for breaking changes in raw-menu-anchor-close-order

[davidhicks980]

Description of what this PR is changing or adding, and why:
Adds a timeline for breaking changes in raw-menu-anchor-close-order. I didn't fill in the stable version yet -- should I?

PRs or commits this PR depends on (if any):
flutter/flutter#182357

@dkwingsmt

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 a Timeline section to the breaking changes documentation for RawMenuAnchor. The review feedback suggests replacing the HTML line break tag with a Markdown list to adhere to style guidelines and improve readability.

[gemini-code-assist]

The use of the <br> tag violates the Google Developer Documentation Style Guidelines, which this PR aims to follow. Instead of using HTML tags for line breaks, use a Markdown list for better structure and consistency with the rest of the document.

Suggested change

	Landed in version: 3.44.0-0.1.pre<br>
	In stable release: TBD
	* Landed in version: 3.44.0-0.1.pre
	* In stable release: TBD

References

1. The Google Developer Documentation Style Guide explicitly advises against using the
   tag and recommends using lists for related items. ^(link)

[flutter-website-bot]

Visit the preview URL for this PR (updated for commit e695cf9):

https://flutter-docs-prod--pr13287-timeline-bm2lqf1r.web.app