Handle if/else statements

[matthewdavidson]

stylelint-config-skyscanner complains that the following scss is invalid:

  @if $direction == 'left' {
    left: 0;
  } @else {
    right: 0;
  }

...and suggest that I do this:

  @if $direction == 'left' {
    left: 0;
  }

  @else {
    right: 0;
  }