Improve markup of Group Settings screen

[mercime]

The legend provides a description for the group of form controls within a fieldset. WCAG 2.0 1.3.1 Info and Relationships

[mercime]

Changed the issue from "Each fieldset requires a corresponding legend element" since further review of source code reveals a11y updates required.

Revisions included in https://gist.github.com/mercime/7e8b41f7a6eccbcad5b4b367bb065e24 are the same as the "accessified" Group Settings screen in bp-legacy :

• Remove outer fieldset without legend for the Group Privacy Options
• Remove outer DL wrapper from the UL which lists descriptions of each radio button
• Add tabindex="0" for description of radio fields under Group Invitations

[mercime]

https://gist.github.com/mercime/6824ec9ee86976a6c77b68cbf3dc3570 includes style updates and revisions

BEFORE

AFTER

[hnla]

Not necessarily happy with these particular changes, I wrote the markup using a DL construct for a reason as it greatly improved on what existed and the DL construct provides for a general description for it's sibling definitions.

Also I did deliberately attempt to move the descriptions or conditions above the input as there is precious little point to them after, but we revert that in your example.

Please discuss this one with me.

[mercime]

Thanks for your feedback. Not quite sure why the new markup was implemented which is why I made the gist above instead of committing the solution so as not to step on anyone's toes.

[mercime]

Thanks for DM in Slack hnla. Updating markup in a few minutes.