Walk testers through cloning into a folder named VanillaGuide (the
.toc filename, not the repo name) under Interface/AddOns/, and ask
them to install BugSack + !BugGrabber so any Lua errors come back as
copy-pasteable stacks instead of vibes.
GuideTable.lua:88 used the Lua 5.0 global getn() to size the color-
substitution table opentext. In Lua 5.1 (WoW 3.3.5) the bare getn is
gone and table.getn is deprecated, so this would have crashed with
'attempt to call global getn (a nil value)' before any guide could
render. Replaced with the # length operator.
Also record the fix and the upstream README cleanup under 'Files we
touched' in README-CoA.md.