updating DIRECTORY.md

Author: github-actions

DIRECTORY.md

@@ -85,9 +85,10 @@
   * [Bubblesort](https://github.com/TheAlgorithms/Go/blob/master/sorts/bubblesort.go)
   * [Countingsort](https://github.com/TheAlgorithms/Go/blob/master/sorts/countingsort.go)
   * [Heap Sort](https://github.com/TheAlgorithms/Go/blob/master/sorts/heap_sort.go)
-  * [Insertionsort](https://github.com/TheAlgorithms/Go/blob/master/sorts/insertionsort.go)
+  * [Insertion Sort](https://github.com/TheAlgorithms/Go/blob/master/sorts/insertion_sort.go)
   * [Merge Sort](https://github.com/TheAlgorithms/Go/blob/master/sorts/merge_sort.go)
   * [Quick Sort](https://github.com/TheAlgorithms/Go/blob/master/sorts/quick_sort.go)
+  * [Radix Sort](https://github.com/TheAlgorithms/Go/blob/master/sorts/radix_sort.go)
   * [Selection Sort](https://github.com/TheAlgorithms/Go/blob/master/sorts/selection_sort.go)
   * [Shell Sort](https://github.com/TheAlgorithms/Go/blob/master/sorts/shell_sort.go)
   * [Sorts Case Test](https://github.com/TheAlgorithms/Go/blob/master/sorts/sorts_case_test.go)