Update the Reference Manual

I found the example about the method styleTags in Reference Manual is outdated

the example still use the parser.withProps method which has removed

Thank you for spotting that. This patch updates the example.

Great!

and find another improvement for System Guide document

missing two command-line options supported by lezer-generator :

I’ve added an item for --typeScript. --help doesn’t seem that useful to someone who’s already looking at documentation.