;; Non raw strings
  ;; 1. if in string, find a fence backwads that is not string
  ;;    interpolation
  ;; 2. now search forward for a matching delimiter, ensuring no
  ;;    non-interpolation fences before then, marking the closing
  ;;    match as fence, unless we reach end. if it's not multiline
  ;;    fence, then mark end of line as delimiter
  ;; 3. if we don't start in a string, search backwards, ensuring we
  ;;    are not in interpolation. if we are, find forward it's match
  ;;    and mark as fence.