docs: public static void appendNormalisedWhitespace(StringBuilder accum, String string, boolean stripLeading) {
          boolean lastWasWhite = false;
          boolean reachedNonWhite = false;
  
          int len = string.length();
          int c;
          for (int i = 0; i < len; i+= Character.charCount(c)) {
              c = string.codePointAt(i);
              if (isActuallyWhitespace(c)) {
                  if ((stripLeading && !reachedNonWhite) || lastWasWhite)
                      continue;
                  accum.append(' ');
                  lastWasWhite = true;
              }
              else if (!isInvisibleChar(c)) {
                  accum.appendCodePoint(c);
                  lastWasWhite = false;
                  reachedNonWhite = true;
              }
          }
      }