Removed `"-*-user-select"` checks.

MDN precisely states that "user-select" is not a standard property.
https://developer.mozilla.org/en-US/docs/Web/CSS/user-select
Closes gh-385
"selector-newline": look for newline characters in selectors

Usually it's a forgotten comma, not a descendant combinator.
Closes gh-282
Specify html lang.