Mark navigator.canShare() experimental+nonstandard (#6844)
Mark navigator.canShare() experimental+nonstandard (#6844)

This change marks the navigator.canShare() method as experimental:true
and standard_track:false, per https://github.com/w3c/web-share/pull/134
and https://github.com/w3c/web-share/pull/134#issuecomment-703653048 in
particular. https://github.com/w3c/web-share/commit/2bbde9c dropped it
as a specified feature (along with the entire Web Share Level 2 spec.)
mdn/browser-compat-data,chrisdavidmills/browser-compat-data,mdn/browser-compat-data,chrisdavidmills/browser-compat-data