WoMan currently assumes 10 characters per inch horizontally, hence a
horizontal resolution of 24 basic units, and 5 lines per inch
vertically, hence a vertical resolution of 48 basic units.
(nroff uses 240 per inch.)
The number of consecutive blank lines in the formatted buffer should be either 0 or 1. A blank line should leave a space like .sp 1. Current policy is to output vertical space only immediately before text is output.