Lint the list of web-features in web-features.json

[captainbrosset]

Once #930 lands, we should find a way to lint the list of web-features in the web-features.json file, to avoid typos and future feature changes.

One example was given by @foolip: the text-wrap feature reference might be impacted by web-platform-dx/web-features#2543. See #930 (comment)