Remove extra asterisk in example in C.60 (#1430)

closes #1429

CppCoreGuidelines.md

@@ -5808,11 +5808,11 @@ But what if you can get significantly better performance by not making a tempora
     {
         if (a.sz > sz) {
             // ... use the swap technique, it can't be bettered ...
-            return *this
+            return *this;
         }
         // ... copy sz elements from *a.elem to elem ...
         if (a.sz < sz) {
-            // ... destroy the surplus elements in *this* and adjust size ...
+            // ... destroy the surplus elements in *this and adjust size ...
         }
         return *this;
     }