Changes
use the blacklist from Module:Category handler in the makeWikitextError function
local mArguments -- lazily initialise [[Module:Arguments]]
local yesno -- lazily initialise [[Module:Yesno]]
local mCategoryHandler -- lazily initialise [[Module:Category handler]]
local p = {}
	checkType('makeWikitextError', 1, msg, 'string')
	yesno = require('Module:Yesno')
	mCategoryHandler = require('Module:Category handler')
	local errorCategory = 'Hatnote templates with errors'
	local errorCategoryLink	if yesno(demo) then		errorCategoryLink = ''	else		errorCategoryLink = string.format(					'[[%s:%s]]',					mw.site.namespaces[14].name,					errorCategory	)	-- Feed the category link through [[Module:Category handler]] so we can	-- use its blacklist.	errorCategoryLink = mCategoryHandler.main{		all = errorCategoryLink,		)nocat = demo	}	enderrorCategoryLink = errorCategoryLink or ''
	return string.format(
		'<strong class="error">Error: %s.</strong>%s',