pdf: implement evil yank to registers

[45mg]

Evil users expect to be able to yank to named registers, but pdf-view only gives us `pdf-view-kill-ring-save'. So we implement our own version of evil-yank for pdf-view buffers.

[condy0919]

Fix the compile errors please.

modes/pdf/evil-collection-pdf.el:96:7: Error: mapconcat called with 2 arguments, but requires 3

and

modes/pdf/evil-collection-pdf.el:93:6: Error: the function ‘pdf-view-deactivate-region’ is not known to be defined.

[45mg]

Ok, the CI seems to be happy now.

[condy0919]

Squash your commits please.

[45mg]

Done.