`IconButton` should have a tooltip by default

[khiga8]

Having a visible label for an IconButton will help users with cognitive disabilities and increase usability for everyone, since it's not always obvious from the icon what action is possible.

In PVC, all IconButton default to having a tooltip (IconButton PVC docs). I recall this decision was made after input from accessibility design. Could we follow the same pattern here?

Relates to: https://github.com/github/accessibility-audits/issues/3171

[iansan5653]

Related to (possibly duplicate of):

• IconButton should include Tooltip by default #2008

[broccolinisoup]

This might need first releasing the Tooltip remediations #3169

[lesliecdubs]

Thanks all, we're going to close this one as a duplicate of #2008. Also agree we should try to ship the Tooltip accessibility remediations #3169 as a next step!