Correctly order groups/descriptions in HelpMenuList

After I added the map context from the keymap.xmls as kind of 'free'
groeping option in the helpmenu list beside the hardcoded descriptions
in the enigma2 when it was ordered on the map context strings then the
ordering was not correct. This resolved the ordering

lib/python/Components/HelpMenuList.py

@@ -234,7 +234,7 @@ def _sortKeyAlpha(self, hlp):
 
 	def _sortHeadingsAlpha(self, a):
 		# ignore case
-		return (getattr(a[0], "description", None) or "").lower()
+		return (getattr(a[0], "description", None) or _(re.sub(r"(\w)([A-Z])([a-z])", r"\1 \2\3", a[1]))).lower()
 
 	def ok(self):
 		# a list entry has a "private" tuple as first entry...