This is the correct markup macro, as opposed to .Va (variable names)
While here, annotate several bare references to `NULL` with .Dv.
r315133:
lib/libcam/cam.3: fix manpage warnings
- spelling: "mis-named" should be "misnamed".
- delete spaces interspersed in literal representation of
`struct cam_device` as hard-tabs separate the types and fields.
- Add commas after `e.g.`.
r315186:
lib/libcam/cam.3: note that cam_freeccb(3) with ccb == NULL is a no-op
This allows me to accurately test this scenario, and for others to rely
on the behavior, instead of relying on knowledge obtained via code
inspection.