Pre LaTeX (I am old...) I wrote a huge command definition document for an embedded telecom product in nroff/troff. The whole thing was text files, with all the common parameters documented once, and the whole thing was assembled using a Makefile. So a typical page would be the command name, a descriptive paragraph, an include list of the parameters it used, and an include list of the possible return errors. Very little writing for a new command that mostly used existing parameters and errors.

And all tracked under CVS with a management/tracking layer on top.

# make command_doc

and the pile of text became a lovely 250 page postcript ready for the laser printer.