Add support of `text-size-adjust` property

[Sergii Lavrin]

 html { text-size-adjust: 100%; }

In some sense it is non-standard property, but it's commonly used by mobile browsers.

Details.

[Viorel Cojocaru]

text-size-adjust was added in the last version: https://github.com/betit/known-css-properties/blob/master/data/all.json#L859 and it is available on Stylelint 7.2.0: stylelint/stylelint@318a978

All the browsers were supporting the prefixed version, though Chrome 54 is now supporting the standard version.

[Sergii Lavrin]

Great, thanks!