Unmappable character for encoding ASCII

picocli won't compile

```
CommandLine.java:3491: error: unmappable character for encoding ASCII
         * The synopsis would show {@code --[no-]force} and {@code -XX:??PrintGCDetails}, respectively.
CommandLine.java:3491: error: unmappable character for encoding ASCII
         * The synopsis would show {@code --[no-]force} and {@code -XX:??PrintGCDetails}, respectively.
```