Several bug fixes and improvements (#945)

* Update Dockerfile for code debugging.

* Format Python code using Black.

* Improve dark theme by defining html classes for the figures, animations and cover images.

* Fix several glossary translation.

* Update a code comment.

* Fix climbing_stairs_backtrack: the pruning should not require the sorted choices list.

* Update the code of array and list traversal.

* Fix a rendering issue of README.md

* Update code of list traversal.

* Fix array_definition.png

* Update README.md

* Fix max_capacity_moving_short_board.png

* Fix array.dart

* Fix array.dart

* Fix array.dart

* Fix array.dart

codes/javascript/chapter_array_and_linkedlist/array.js

@@ -50,11 +50,11 @@ function traverse(nums) {
     let count = 0;
     // 通过索引遍历数组
     for (let i = 0; i < nums.length; i++) {
-        count++;
+        count += nums[i];
     }
-    // 直接遍历数组
+    // 直接遍历数组元素
     for (const num of nums) {
-        count += 1;
+        count += num;
     }
 }