Menu Customizer: add aria-expanded attribute to Edit menu item toggles

[afercia]

As done for other Toggle controls in the Customizer, also the Edit Menu Item buttons would need an aria-expanded attribute to inform users they control an expandable panel placed right after them.

This would imply to rework the toggle arrows to avoid the same NVDA bug noticed for other toggles, see: https://core.trac.wordpress.org/ticket/32715#comment:13
Side note: I've submitted a ticket in the NVDA bug tracker, with a reduced test case, we will see. ​http://community.nvda-project.org/ticket/5247

[afercia]

In the proposed patch:

• add an aria-expanded attribute to the Edit Menu Item buttons and update it dynamically depending on the panel expanded/collapsed status

See in the screenshot below, going back and forth through the toggle buttons and activating them in Firefox + NVDA (arrows indicate when the toggle button was activated):

[obenland]

Let's do that in a future release, we're two days away from RC.

[SergeyBiryukov]

IIRC, we used to fix accessibility bugs with newly added features during the same cycle, even after RC.

[samuelsidler]

I agree with Sergey. Let's at least keep this on the milestone and punt at the last minute if we run out of time.

[celloexpressions]

Most of the accessibility items we've had after core merge for menus in the Customizer have really been more toward enhancements than bugs. There are a lot of moving pieces here and the JS is not straightforward. I would caution against making many more of these types of fixes at this point as there's a high likelihood that there will be unexpected breakage even with only minimal code churn.

I don't want to minimize the importance of fixing the issues that remain, but after all of the reviewing that's happened to date I imagine things being discovered now are generally lower priority or regressions from things that have already been fixed once.

[ocean90]

In 33483:

Customizer: Add an aria-expanded attribute to Edit menu item toggles.

props afercia.
fixes #33129.

[westonruter]

There seems to be a regression introduced in [33483]. See 33129-regression.png​. When dragging a menu item which is expanded, I'm seeing the post title replacing the toggle indicator.

[ocean90]

This is not a really a regression. The bug is now only visually present too. Previously the title was added to the button directly, see 33129-before.png​. The titel comes from refreshAdvancedAccessibilityOfItem() in nav-menu.js.

[afercia]

Maybe consider to add a comment in 33129.2.patch​ to explain why the "a" in the selector a.item-edit must be there.

[ocean90]

In 33502:

Nav menus: Make the selector for the edit menu item link more specific. Prevents clashing with other elements which have the same class.

fixes #33129.