Support for Focusgroup minimum role

[mehm8128]

A new focusgroup HTML attribute has been proposed and implemented in browsers, and yesterday Chromium announced an Intent to Ship for Chromium v150.

This feature makes it easier to implement the Roving tabindex UI pattern for elements such as radio groups, tabs, toolbars, and etc.
Request for developer feedback: focusgroup  |  Blog  |  Chrome for Developers

Once developers provide the focusgroup attribute with a "behavior" token such as toolbar, tablist, radiogroup, and so on to a focusgroup container, the container is given a minimum container role and its children are given a minimum child role.
behavior tokens table: https://developer.chrome.com/blog/focusgroup-rfc#behavior_tokens
minimum role: https://w3c.github.io/html-aam/#minimum-role

This means that even though the HTML elements have no implicit or explicit role, if they have a minimum role provided by the focusgroup attribute, they effectively have a role. This behavior affects static lint analytics.

Example: radiogroup
We can implemenet a radiogroup with the following sample code using focusgroup.

<div
  focusgroup="radiogroup block wrap"
  aria-label="Favorite color"
  class="radio-group"
>
  <span
    aria-checked="true"
    tabIndex="0"
    class="radio-option checked"
    focusgroupstart
  >
    Red
  </span>
  <span tabIndex="0" class="radio-option">
    Green
  </span>
  <span aria-checked="false" tabIndex="0" class="radio-option">
    Blue
  </span>
  <span aria-checked="false" tabIndex="0" class="radio-option">
    Purple
  </span>
</div>

Here, <div class="radio-group"> is a focusgroup container with a minimum role of radiogroup, and <span class="radio-option"> is a focusgroup child with a minimum role of radio.
Even though the radio role with tabIndex="0" is valid and radio role requires the aria-checked attribute, for now Biome mistakenly detects tabIndex="0" as an invalid declaration and overlooks the fact that the Green radio item is missing the aria-checked attribute.

Therefore, in order to support focusgroup minimum roles, we need to reconsider some lint rules that deal with ARIA roles.

While focusgroup has not yet shipped in Chrome stable and other browsers, investigating the scope of impact and considering ways to address this issue will make it easier to adopt this new feature when it becomes available.