Avoid duplicate numbers in sub-group size example

Author: Pennycook

adoc/chapters/architecture.adoc

@@ -1242,9 +1242,9 @@ the same number of work-items.
 Otherwise, the division of a work-group into sub-groups is
 implementation-defined.
 
-{note}For example, a two-dimensional work-group of size {3, 3} with a maximum
+{note}For example, a two-dimensional work-group of size {2, 3} with a maximum
 sub-group size of 16 may be split into two sub-groups of size 3, or treated as a
-single sub-group of size 9.{endnote}
+single sub-group of size 6.{endnote}
 
 The numbering of work-items in a sub-group reflects the linear numbering of the
 work-items in the work-group.