feat: add swift implementation to lcci problem: No.16.05 (doocs#2728)

Author: klever34

lcci/16.05.Factorial Zeros/README.md

@@ -93,6 +93,20 @@ function trailingZeroes(n: number): number {
 }
 ```
 
+```swift
+class Solution {
+    func trailingZeroes(_ n: Int) -> Int {
+        var count = 0
+        var number = n
+        while number > 0 {
+            number /= 5
+            count += number
+        }
+        return count
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

lcci/16.05.Factorial Zeros/README_EN.md

@@ -101,6 +101,20 @@ function trailingZeroes(n: number): number {
 }
 ```
 
+```swift
+class Solution {
+    func trailingZeroes(_ n: Int) -> Int {
+        var count = 0
+        var number = n
+        while number > 0 {
+            number /= 5
+            count += number
+        }
+        return count
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- end -->

lcci/16.05.Factorial Zeros/Solution.swift

@@ -0,0 +1,11 @@
+class Solution {
+    func trailingZeroes(_ n: Int) -> Int {
+        var count = 0
+        var number = n
+        while number > 0 {
+            number /= 5
+            count += number
+        }
+        return count
+    }
+}