Improve the consistency between code and comments in Kotlin (#1268)

* style(kotlin): Make code and comments consistent.

* style(kotlin): convert comment location.

* style(c): Add missing comment.

* style(kotlin): Remove redundant semicolon, parenthesis and brace

* style(kotlin): Put constants inside the function.

* style(kotlin): fix unnecessary indentation.

* style(swift): Add missing comment.

* style(kotlin): Add missing comment.

* style(kotlin): Remove redundant comment.

* style(kotlin): Add missing comment.

* Update linked_list.kt

* style(csharp,js,ts): Add missing comment.

* style(kotlin): Remove empty lines.

* Update list.cs

* Update list.js

* Update list.ts

* roll back to commit 1

* style(cs,js,ts): Add missing comment in docfile.

* style(kotlin): Use normal element swapping instead of scope functions.

codes/swift/chapter_dynamic_programming/climbing_stairs_backtrack.swift

@@ -16,7 +16,9 @@ func backtrack(choices: [Int], state: Int, n: Int, res: inout [Int]) {
         if state + choice > n {
             continue
         }
+        // 尝试：做出选择，更新状态
         backtrack(choices: choices, state: state + choice, n: n, res: &res)
+        // 回退
     }
 }