fix(csharp): Modify method name to PascalCase, simplify new expression (#840)

* Modify method name to PascalCase(array and linked list)

* Modify method name to PascalCase(backtracking)

* Modify method name to PascalCase(computational complexity)

* Modify method name to PascalCase(divide and conquer)

* Modify method name to PascalCase(dynamic programming)

* Modify method name to PascalCase(graph)

* Modify method name to PascalCase(greedy)

* Modify method name to PascalCase(hashing)

* Modify method name to PascalCase(heap)

* Modify method name to PascalCase(searching)

* Modify method name to PascalCase(sorting)

* Modify method name to PascalCase(stack and queue)

* Modify method name to PascalCase(tree)

* local check

codes/csharp/chapter_searching/hashing_search.cs

@@ -8,14 +8,14 @@ namespace hello_algo.chapter_searching;
 
 public class hashing_search {
     /* 哈希查找（数组） */
-    static int hashingSearchArray(Dictionary<int, int> map, int target) {
+    static int HashingSearchArray(Dictionary<int, int> map, int target) {
         // 哈希表的 key: 目标元素，value: 索引
         // 若哈希表中无此 key ，返回 -1
         return map.GetValueOrDefault(target, -1);
     }
 
     /* 哈希查找（链表） */
-    static ListNode? hashingSearchLinkedList(Dictionary<int, ListNode> map, int target) {
+    static ListNode? HashingSearchLinkedList(Dictionary<int, ListNode> map, int target) {
 
         // 哈希表的 key: 目标节点值，value: 节点对象
         // 若哈希表中无此 key ，返回 null
@@ -33,7 +33,7 @@ public class hashing_search {
         for (int i = 0; i < nums.Length; i++) {
             map[nums[i]] = i;  // key: 元素，value: 索引
         }
-        int index = hashingSearchArray(map, target);
+        int index = HashingSearchArray(map, target);
         Console.WriteLine("目标元素 3 的索引 = " + index);
 
         /* 哈希查找（链表） */
@@ -44,7 +44,7 @@ public class hashing_search {
             map1[head.val] = head;  // key: 节点值，value: 节点
             head = head.next;
         }
-        ListNode? node = hashingSearchLinkedList(map1, target);
+        ListNode? node = HashingSearchLinkedList(map1, target);
         Console.WriteLine("目标节点值 3 的对应节点对象为 " + node);
     }
 }