Rebuild doc/*.txt (other than Guidebook) with 'nroff -man -c -Tascii'
rather than just 'nroff -man' to prevent it generating non-ASCII
characters for hyphen, aprostrophe, single and double quotes, long
dash, possibly others. Also preprocess with '--grep-define ALLDOCS'
so that a few parts of the text don't end up being specific to the
local configuration.
The next time they're rebuilt they'll probably be subject to the
ping-pong effect of inserting padding spaces for justification
(alternating right-to-left vs left-to-right as intended but starting
with different parity so lots of gratuitous changes) since my quite
old version of groff triggers that for Guidebook.txt.
Update makdefs source and its man page.
Remove all mentions of the vision table files from:
o .gitattributes
o .gitignore
o Files
o Cross-compiling
Add a brief note in the fixes file.
