feat: add rust solution to lc problem: No.0136 (doocs#668)

No.0136. Single Number

Author: YangFong

solution/0100-0199/0136.Single Number/README.md

@@ -105,6 +105,20 @@ public:
 };
 ```
 
+### **Rust**
+
+```Rust
+impl Solution {
+    pub fn single_number(nums: Vec<i32>) -> i32 {
+        let mut result = 0;
+        for num in nums {
+            result ^= num;
+        }
+        result
+    }
+}
+```
+
 ### **...**
 
 ```

solution/0100-0199/0136.Single Number/README_EN.md

@@ -100,6 +100,20 @@ public:
 };
 ```
 
+### **Rust**
+
+```Rust
+impl Solution {
+    pub fn single_number(nums: Vec<i32>) -> i32 {
+        let mut result = 0;
+        for num in nums {
+            result ^= num;
+        }
+        result
+    }
+}
+```
+
 ### **...**
 
 ```

solution/0100-0199/0136.Single Number/Solution.rs

@@ -0,0 +1,9 @@
+impl Solution {
+    pub fn single_number(nums: Vec<i32>) -> i32 {
+        let mut result = 0;
+        for num in nums {
+            result ^= num;
+        }
+        result
+    }
+}