Accessibility: Use semantic button elements instead of empty links in Profile visibility settings

[mercime]

The profile visibility links in the following screens: Profile > Edit, Registration, and wp-admin Users - Member > Extended Profile should be buttons instead of empty links for proper semantics and accessibility.

• Change empty link to button element
• Close empty link to button element

Patch and screenshots coming up.

[mercime]

Before and After using the Twenty Sixteen theme

[dontdream]

@mercime: please note there is a surviving href="#" inside the last <button> element.

[mercime]

@dontdream Thank you :) Updated patch coming up.

[DJPaul]

Patch LGTM.

[mercime]

In 11246:

Accessibility: Use <button> elements in Profile visibility settings.

Replace empty links <a href="#"> with semantic <button> elements for
semantics and accessibility.

Fixes #7358.

[mercime]

In 11410:

Credits: Add @dontdream to contributor list.
Thank you.

See #7358.