updating DIRECTORY.md

Author: github-actions

DIRECTORY.md

@@ -110,6 +110,9 @@
   * Modulararithmetic
     * [Modularexponentiation](https://github.com/TheAlgorithms/Go/blob/master/math/modulararithmetic/modularexponentiation.go)
     * [Modularexponentiation Test](https://github.com/TheAlgorithms/Go/blob/master/math/modulararithmetic/modularexponentiation_test.go)
+  * Permutation
+    * [Heaps](https://github.com/TheAlgorithms/Go/blob/master/math/permutation/heaps.go)
+    * [Heaps Test](https://github.com/TheAlgorithms/Go/blob/master/math/permutation/heaps_test.go)
   * Power
     * [Fastexponent](https://github.com/TheAlgorithms/Go/blob/master/math/power/fastexponent.go)
     * [Fastexponent Test](https://github.com/TheAlgorithms/Go/blob/master/math/power/fastexponent_test.go)
@@ -123,9 +126,6 @@
   * Sieve
     * [Sieve](https://github.com/TheAlgorithms/Go/blob/master/math/sieve/Sieve.go)
     * [Sieve Test](https://github.com/TheAlgorithms/Go/blob/master/math/sieve/sieve_test.go)
-  * Permutation
-    * [Heap's Algorithm](https://github.com/TheAlgorithms/Go/blob/master/math/permutation/heaps.go)
-    * [Heap's Algorithm Test](https://github.com/TheAlgorithms/Go/blob/master/math/permutation/heaps_test.go)
 
 ## Other
   * Maxsubarraysum