Fix the match notation in heap_lang for option.

heap_lang/notation.v

@@ -114,6 +114,6 @@ Notation SOMEV x := (InjRV x).
 Notation "'match:' e0 'with' 'NONE' => e1 | 'SOME' x => e2 'end'" :=
   (Match e0 BAnon e1 x%bind e2)
   (e0, e1, x, e2 at level 200) : expr_scope.
-Notation "'match:' e0 'with' 'SOME' x => e2 | 'NONE' => e1 |  'end'" :=
+Notation "'match:' e0 'with' 'SOME' x => e2 | 'NONE' => e1 'end'" :=
   (Match e0 BAnon e1 x%bind e2)
   (e0, e1, x, e2 at level 200, only parsing) : expr_scope.