code: @SuppressWarnings("unused") // called in SoyFileParser.jj
    public static String unescapeString(String s, ErrorReporter errorReporter, SourceLocation loc) {
      StringBuilder sb = new StringBuilder(s.length());
      for (int i = 0; i < s.length(); ) {
        char c = s.charAt(i);
        if (c == '\\') {
          i = doUnescape(s, i + 1, sb, errorReporter, loc);
        } else {
          sb.append(c);
          i++;
        }
      }
      return sb.toString();
    }
docs: Unescapes a Soy string, according to JavaScript rules.