Consider separating `text-autospace`'s two-value syntax into a separate feature

[ddbeck]

Chrome, Firefox, and Safari support part of the text-autospace feature (source, dist): text-autospace: no-autospace and text-autospace: normal. There's a plausible split here, like this:

One-value syntax (the existing feature), with these keys:

• css.properties.text-autospace
• css.properties.text-autospace.auto
• css.properties.text-autospace.no-autospace
• css.properties.text-autospace.normal

Two-value syntax, with these keys:

• css.properties.text-autospace.ideograph-alpha
• css.properties.text-autospace.ideograph-numeric
• css.properties.text-autospace.insert
• css.properties.text-autospace.punctuation
• css.properties.text-autospace.replace

At the time that I'm writing this, neither feature would be Baseline low (because Chrome doesn't support auto), but some keys in the one-value feature would be. No part of the two-value feature would be Baseline.

I found this while reviewing #3536.