Bug in `RTFMakeSafeText` in `URTFUtils` unit

https://github.com/delphidabbler/codesnip/blob/131d602e533af0496c2e2744e2edce73270a475d/Src/URTFUtils.pas#L240

The line

```pascal
else if (Ch = '{') or (Ch = '\') or (Ch = '}') then
```

should be

```pascal
else if (AnsiCh = '{') or (AnsiCh = '\') or (AnsiCh = '}') then
```
