Autofocus first item when open menu

[brunoprietog]

Hi,

Will it be possible to focus the first menu item when it opens without it being an input element necessarily? This is how it is currently defined.

For accessibility, in most dropdowns, when pressing the button, the focus is expected to go to the first menu item, that doesn't happen currently.

I can try to make a pr to fix this if you agree.

Thanks!

[brunoprietog]

I also noticed when reading the code that the autofocus attribute of details-menu is not documented. Perhaps one could also add