Many bug fixes and improvements (#1270)

* Add Ruby and Kotlin icons
Add the avatar of @curtishd

* Update README

* Synchronize zh-hant and zh versions.

* Translate the pythontutor blocks to traditional Chinese

* Fix en/mkdocs.yml

* Update the landing page of the en version.

* Fix the Dockerfile

* Refine the en landingpage

* Fix en landing page

* Reset the README.md

zh-hant/codes/rust/chapter_hashing/hash_map_chaining.rs

@@ -102,17 +102,14 @@ impl HashMapChaining {
         // 走訪桶，若遇到指定 key ，則更新對應 val 並返回
         for pair in bucket {
             if pair.key == key {
-                pair.val = val.clone();
+                pair.val = val;
                 return;
             }
         }
         let bucket = &mut self.buckets[index];
 
         // 若無該 key ，則將鍵值對新增至尾部
-        let pair = Pair {
-            key,
-            val: val.clone(),
-        };
+        let pair = Pair { key, val };
         bucket.push(pair);
         self.size += 1;
     }