Add `Element.createShadowRoot(…)`
Add `Element.createShadowRoot(…)`

  `Element.createShadowRoot(…)` was the Shadow DOM v0 equivalent
of `Element.attachShadow(…)` from Shadow DOM v1, but has somewhat
different semantics from its Shadow DOM v1 counterpart.

  It was removed in Firefox 61 by https://bugzil.la/1453789.

teoli2003/browser-compat-data,chrisdavidmills/browser-compat-data,mdn/browser-compat-data,mdn/browser-compat-data,chrisdavidmills/browser-compat-data