doc: Add helper for converting DocBook files to Markdown

maintainers/scripts/doc/unknown-code-language.lua

@@ -0,0 +1,12 @@
+--[[
+Adds “unknown” class to CodeBlock AST nodes without any classes.
+
+This will cause Pandoc to use fenced code block, which we prefer.
+]]
+
+function CodeBlock(elem)
+  if #elem.classes == 0 then
+    elem.classes:insert('unknown')
+    return elem
+  end
+end