OpenSystemsDevelopment / qpdf

...when flattening annotations. This includes /Link, /Popup,
and /Projection.

Rather than adding yet another flag that is almost never useful on its
own, just have --remove-restrictions disable digital signatures. The
operations are still separate in the API.

Positional arguments are supported in a backward-compatible way, but
completion no longer guides users to it.

Add the command-line arguments. They don't do anything yet.

JSON accepts scientific notation, but PDF doesn't.

To reference another command line option description, `:qpdf:ref:` is needed instead of `:qpdf:option:` which is not resolved properly in the HTML documentation.

Future

Also enforce in format-code.