code: static public String getPathToRoot(JBakeConfiguration config, File rootPath, File sourceFile) {
  
          Path r = Paths.get(rootPath.toURI());
          Path s = Paths.get(sourceFile.getParentFile().toURI());
          Path relativePath = s.relativize(r);
  
          StringBuilder sb = new StringBuilder();
  
          sb.append(asPath(relativePath.toString()));
  
          if (config.getUriWithoutExtension()) {
              sb.append("/..");
          }
          if (sb.length() > 0) {  // added as calling logic assumes / at end.
              sb.append("/");
          }
          return sb.toString();
      }
docs: Given a file inside content it return
  the relative path to get to the root.
  <p>
  Example: /content and /content/tags/blog will return '../..'
  
  @param sourceFile the file to calculate relative path for
  @return