[Groff] pvs request

[Werner LEMBERG]

Another undocumented treasure which I've discovered.

From groff_diff.man:

       .pvs ±n
              Set  the  post-vertical  line  space  to n; default
              scale indicator is p.  This value will be added  to
              each  line after it has been output.  With no argu-
              ment, the post-vertical line space is  set  to  its
              previous value.

              The  total  vertical  line spacing consists of four
              components: .vs and \x with a negative value  which
              are applied before the line is output, and .pvs and
              \x with a positive value which  are  applied  after
              the line is output.

       \n[.pvs]
              The  current  post-vertical  line space as set with
              the pvs request.


    Werner