private static void unescapeChar(@NotNull StringBuilder buf, @NotNull String str, char unescapeChar) {
    int length = str.length();
    int last = length - 1;
    for (int i = 0; i < length; i++) {
      char ch = str.charAt(i);
      if (ch == '\\' && i != last) {
        //noinspection AssignmentToForLoopParameter
        i++;
        ch = str.charAt(i);
        if (ch != unescapeChar) buf.append('\\');
      }

      buf.append(ch);
    }
  }
private static void unescapeChar(@NotNull StringBuilder buf, @NotNull String str, char unescapeChar)