Include "PDF" in package description for apt search

The zathura package doesn't show up when searching for packages with "PDF" in their descriptions (such as with apt search pdf) making it harder for somebody searching for a PDF viewer to find it.

Obviously the zathura package itself doesn't directly include the PDF support, but since zathura depends on zathura-pdf-poppler, anybody installing zathura does in practice get a PDF viewer. It isn't possible to have zathura without its being able to view PDF documents.

For instance changing the first line of its description from:

“zathura is a document viewer with a minimalistic and space saving interface.”

to something like

“zathura is a document viewer for PDF and other formats, with a minimalistic and space saving interface.”

would make the description more useful, and Zathura more findable.

The zathura-pdf-poppler package obviously does show up in apt search pdf, but that doesn't necessarily help somebody searching for a PDF viewer. Its description is simply “PDF support for zathura”; if you don't already know what Zathura is, then there's nothing in that description which indicates that this will provide a PDF viewer, rather than adding PDF support to any other kind of software. Especially if you haven't heard of Poppler either.

Changing zathura-pdf-poppler's description to “PDF support for the zathura document viewer” would be an improvement ‒ but getting ‘PDF’ into the main package's description somewhere would be even better.