message: Support web notation for hex colors
diff: @@ -965,8 +965,11 @@ impl FromStr for Rgb {
  }
  }
  - if chars.next().unwrap() != '0' { return Err(()); }
  - if chars.next().unwrap() != 'x' { return Err(()); }
  + match chars.next().unwrap() {
  + '0' => if chars.next().unwrap() != 'x' { return Err(()); },
  + '#' => (),
  + _ => return Err(()),
  + }
  component!(r, g, b);
  