Fix Lua 5.0 getn() crash on first guide load

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.

GuideTable.lua

@@ -85,7 +85,7 @@ function objGuideTable:new(oSettings)
 								["replace"] = "|c00a80000"
 							},
 						}
-						for n = 1, getn(opentext) do
+						for n = 1, #opentext do
 							t1[k1].items[k2].str = gsub(t1[k1].items[k2].str, opentext[n]["find"],opentext[n]["replace"])
 						end
 						t1[k1].items[k2].str = gsub(t1[k1].items[k2].str, "#","|r")

README-CoA.md

@@ -27,6 +27,13 @@ have thrown `attempt to index global 'arg' (a nil value)` on every
 debug call. Local-shadow `arg = {...}` keeps the rest of each function
 unchanged.
 
+**3. Lua 5.0 `getn` → length operator.** `GuideTable.lua` used the
+Lua 5.0 global `getn(opentext)` to size a colour-substitution table.
+That global is gone in Lua 5.1 (`table.getn` was deprecated and the
+bare `getn` removed entirely). Replaced with `#opentext`. Would have
+crashed on the very first guide load with
+`attempt to call global 'getn' (a nil value)`.
+
 What is still TODO
 ------------------
 
@@ -57,6 +64,8 @@ Files we touched
 
 - `VanillaGuide.toc` — Interface bump, CoA metadata.
 - `Core.lua` — local-shadow `arg = {...}` inside `Di` and `Dv`.
+- `GuideTable.lua` — `getn(opentext)` → `#opentext`.
+- `README.md` — upstream Donations / volunteer-pitch section removed.
 - `README-CoA.md` — this file.
 
 Everything else is the unmodified 1.04.2 import.