Update README.markdown

Author: carlosaking

Diff for: Shell Sort/README.markdown

@@ -117,24 +117,10 @@ Here is an implementation of Shell Sort in Swift:
 var arr = [64, 20, 50, 33, 72, 10, 23, -1, 4, 5]
 
 public func shellSort(_ list: inout [Int]) {
-    
     var sublistCount = list.count / 2
-   
     while sublistCount > 0 {
-        
-        for index in 0..<list.count {
-           
-            guard index + sublistCount < list.count else { break }
-            
-            if list[index] > list[index + sublistCount] {
-                swap(&list[index], &list[index + sublistCount])
-            }
-            
-            guard sublistCount == 1 && index > 0 else { continue }
-            
-            if list[index - 1] > list[index] {
-                swap(&list[index - 1], &list[index])
-            }
+        for pos in 0..<sublistCount {
+            insertionSort(&list, start: pos, gap: sublistCount)
         }
         sublistCount = sublistCount / 2
     }