…currently not supported.

* Update browser support
* Update link. Current one points to IE10 dev guide home page
* Change description so it doesn’t sound like it is talking about a JS
property. Mention it is non-standard, and give advice to look into
transform: scale() instead. Likely this will be mostly used for fixing
old IE hasLayout bugs, but doesn’t harm to mention for people that
accidentally use it instead of the standard property.

…had enabled the flag in initial testing

…gradients are valid too.