CLEANUP: fix typos in comments for contrib/spoa_example
Fixes 3 common typos in the comments of the contrib/spoa_example
subsystem.
diff --git a/contrib/spoa_example/include/mini-clist.h b/contrib/spoa_example/include/mini-clist.h
index 0560456..a89255c 100644
--- a/contrib/spoa_example/include/mini-clist.h
+++ b/contrib/spoa_example/include/mini-clist.h
@@ -57,7 +57,7 @@
#define LIST_NEXT(lh, pt, el) (LIST_ELEM((lh)->n, pt, el))
-/* returns a pointer of type <pt> to a structure preceeding the element
+/* returns a pointer of type <pt> to a structure preceding the element
* which contains list head <lh>, which is known as element <el> in
* struct pt.
*/