Review Swift codes (#1150)

* feat(swift): review for chapter_computational_complexity

* feat(swift): review for chapter_data_structure

* feat(swift): review for chapter_array_and_linkedlist

* feat(swift): review for chapter_stack_and_queue

* feat(swift): review for chapter_hashing

* feat(swift): review for chapter_tree

* feat(swift): add codes for heap article

* feat(swift): review for chapter_heap

* feat(swift): review for chapter_graph

* feat(swift): review for chapter_searching

* feat(swift): review for chapter_sorting

* feat(swift): review for chapter_divide_and_conquer

* feat(swift): review for chapter_backtracking

* feat(swift): review for chapter_dynamic_programming

* feat(swift): review for chapter_greedy

* feat(swift): review for utils

* feat(swift): update ci tool

* feat(swift): trailing closure

* feat(swift): array init

* feat(swift): map index

codes/swift/chapter_greedy/max_capacity.swift

@@ -7,7 +7,7 @@
 /* 最大容量：贪心 */
 func maxCapacity(ht: [Int]) -> Int {
     // 初始化 i, j，使其分列数组两端
-    var i = 0, j = ht.count - 1
+    var i = ht.startIndex, j = ht.endIndex - 1
     // 初始最大容量为 0
     var res = 0
     // 循环贪心选择，直至两板相遇