Docs: Use proper <button> instead of faked <a> element for popover example

[patrickhlauke]

sidesteps #31391 but on principle should really use <button> here

[patrickhlauke]

only browser that currently seems to have a problem with this, from testing, is Safari. investigating further what its beef is...

might set this to draft in meantime...wasn't expecting it to take that long, but seems the shortcoming/quirk there is not as straightforward as initially suspected.

[patrickhlauke]

ok, root of the problem seems to be the fact that Safari doesn't actually focus elements like <button> when you click them with the mouse. which is ... not ideal https://twitter.com/patrick_h_lauke/status/1289988990146211840

and Firefox/Mac copied that silly behavior too. good good. considering adding some basic additional behavior that also sets focus() when clicking these controls...

[patrickhlauke]

will likely keep this PR parked, do a separate PR for a potential cross-browser fix (or, well, a patch for Safari and Firefox on Mac), and hopefully this can then get merged when that fix is merged

[XhmikosR]

@patrickhlauke do we close this?

[patrickhlauke]

yeah as i get the feeling Apple are in no rush to change their behaviour in Safari (and Firefox will just copy what Safari does on macOS for "platform consistency"), and since I doubt we want to hack away at adding extra scripting that explicitly focuses the button after a click ... i think i'll just abandon this. annoying.