Manual: Query syntax is documented on closed corpus

[BeritJanssen]

Right now, all the examples in the query.md section of the manual are taken from the "Dutch Annual Reports" corpus. This documentation was originally made by José for the researchers of that project, but especially the section of examples with query / hits isn't very useful this way.

Alternatives:

• use an open (&English language?) corpus instead. E.g., Goodreads, or Parliament-Netherlands, if we're fine with Dutch examples
• ask if the "Dutch Annual Reports" (which is, contrary to the Dutch origin, English language) may be opened to everyone.

I suspect that option 2 wouldn't be met with much resistance, and would be less work.

[lukavdplas]

Perhaps we should keep an eye out for a small public-domain English dataset that we can use for examples / demos.

[BeritJanssen]

I also noticed that the reported numbers actually don't match. The manual was probably written for an older (smaller) version of the corpus ("Dutch Banking"), which only included financial reports of banks.