* Add semantic color keywords This is based on the list I proposed at https://github.com/badges/shields/issues/1522#issuecomment-456455618. As I started documenting `default` I realized it didn't feel quite right. It's not semantic in relation to the content the way the others are, and it's also not the default left color. I changed it to `disabled` which isn't perfect, but seems better. I'm open to other suggestions. I updated the documentation but the colors won't render correctly until this is deployed Close #1522 * Reformat the aliases * Pretty up the docs * Reset whitespace changes * Clean lint