Add real values for Firefox for Window API (#7532)
Add real values for Firefox for Window API (#7532)

Removes unneeded note which is now on MDN instead:
https://wiki.developer.mozilla.org/en-US/docs/Web/API/Window/sizeToContent.
chrisdavidmills/browser-compat-data,mdn/browser-compat-data,mdn/browser-compat-data,chrisdavidmills/browser-compat-data