message: Fix `show-whitespace` peekaboo bug
diff: line-height: 1em;
  background-clip: border-box;
  background-repeat: repeat-x;
  - background-position: left center;
  + /* 2px because of #4991 */
  + background-position: 2px center;
  }
  [data-rgh-whitespace='tab'] {
  