added link for is_heap.md

Author: rotarymars

reference/algorithm/is_heap.md

@@ -69,6 +69,12 @@ int main()
 }
 ```
 * std::is_heap[color ff0000]
+* std::vector[link /reference/vector/vector.md]
+* std::cout[link /reference/iostream/cout.md]
+* std::boolalpha[link /reference/ios/boolalpha.md]
+* std::endl[link /reference/ostream/endl.md]
+* v.begin[link /reference/vector/vector/begin.md]
+* v.end[link /reference/vector/vector/end.md]
 * std::make_heap[link make_heap.md]
 
 ### 出力