refactor(menu): adjust styling for disabled drill-in chevron

[jawinn]

Description

Some difficulty was encountered with the SWC implementation making sure the chevron on a disabled drill-in menu item displayed as disabled, without overriding CSS. On the SWC end, the way a generic icon is styled is different from how chevrons or checkmarks are styled, so the styles added didn't apply to the chevron.

Discussion here https://github.com/adobe/spectrum-css/pull/2199#pullrequestreview-1881393032

Docs migration guide: also adds versions and dates to the existing migration guide content to conform with new recommended format.

How and where has this been tested?

Please tag yourself on the tests you've marked complete to confirm the tests have been run by someone other than the author.

Validation steps

• [ ] Confirm that solution will work for SWC.
• [ ] Chevron on drill-in menu items continues to look the same in Spectrum CSS, including for a disabled menu item.

Regression testing

Validate:

1. The documentation pages for at least two other components are still loading, including:

• [ ] The pages render correctly, are accessible, and are responsive.

2. If components have been modified, VRTs have been run on this branch:

• [ ] VRTs have been run and looked at.
• [ ] Any VRT changes have been accepted (by reviewer and/or PR author), or there are no changes.

Screenshots

To-do list

• [x] I have read the contribution guidelines.
• [x] I have updated relevant storybook stories and templates.
• [ ] I have tested these changes in Windows High Contrast mode.
• [x] If my change impacts other components, I have tested to make sure they don't break.
• [x] If my change impacts documentation, I have updated the documentation accordingly.
• [ ] ✨ This pull request is ready to merge. ✨

[github-actions[bot]]

File metrics

Summary

Total size: 3.94 MB^* Total change (Δ): ⬆ 0.77 KB (0.02%) Table reports on changes to a package's main file. Other changes can be found in the collapsed "Details" below.

Package	Size	Δ
menu	41.36 KB	⬆ 0.26 KB

Details

menu

File	Head	Base	Δ
index-base.css	41.36 KB	41.11 KB	⬆ 0.26 KB (0.61%)
index-vars.css	41.36 KB	41.11 KB	⬆ 0.26 KB (0.61%)
index.css	41.36 KB	41.11 KB	⬆ 0.26 KB (0.61%)
mods.json	3.33 KB	3.33 KB	-

* Size determined by adding together the size of the main file for all packages in the library.
* Results are not gzipped or minified.
* An ASCII character in UTF-8 is 8 bits or 1 byte.

[github-actions[bot]]

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