Update array.md & hash_map.md (#827)

* Update array.md

- Update array.md
- Add comments to maintain consistency with implementations in other languages.

* Update hash_map.md

- Update hash_map.md
- Update the filename to correspond with the filenames in the "codes/go" directory.

docs/chapter_array_and_linkedlist/array.md

@@ -100,6 +100,7 @@
 === "C"
 
     ```c title="array.c"
+    /* 初始化数组 */
     int arr[5] = { 0 }; // { 0, 0, 0, 0, 0 }
     int nums[5] = { 1, 3, 2, 5, 4 };
     ```

docs/chapter_hashing/hash_map.md

@@ -120,7 +120,7 @@
 
 === "Go"
 
-    ```go title="hash_map.go"
+    ```go title="hash_map_test.go"
     /* 初始化哈希表 */
     hmap := make(map[int]string)