feat: add rust solution to lc problem: No.0470 (doocs#1354)

* feat: add rust solution to lc problem: No.0470

* fix: update

Author: thinkasany

solution/0400-0499/0470.Implement Rand10() Using Rand7()/README.md

@@ -176,6 +176,29 @@ function rand10(): number {
 }
 ```
 
+### **Rust**
+
+```rust
+/**
+ * The rand7() API is already defined for you.
+ * @return a random integer in the range 1 to 7
+ * fn rand7() -> i32;
+ */
+
+impl Solution {
+    pub fn rand10() -> i32 {
+        loop {
+            let i = rand7() - 1;
+            let j = rand7();
+            let x = i * 7 + j;
+            if x <= 40 {
+                return (x % 10) + 1;
+            }
+        }
+    }
+}
+```
+
 ### **...**
 
 ```

solution/0400-0499/0470.Implement Rand10() Using Rand7()/README_EN.md

@@ -139,6 +139,29 @@ function rand10(): number {
 }
 ```
 
+### **Rust**
+
+```rust
+/**
+ * The rand7() API is already defined for you.
+ * @return a random integer in the range 1 to 7
+ * fn rand7() -> i32;
+ */
+
+impl Solution {
+    pub fn rand10() -> i32 {
+        loop {
+            let i = rand7() - 1;
+            let j = rand7();
+            let x = i * 7 + j;
+            if x <= 40 {
+                return (x % 10) + 1;
+            }
+        }
+    }
+}
+```
+
 ### **...**
 
 ```

solution/0400-0499/0470.Implement Rand10() Using Rand7()/Solution.rs

@@ -0,0 +1,18 @@
+/** 
+ * The rand7() API is already defined for you.
+ * @return a random integer in the range 1 to 7
+ * fn rand7() -> i32;
+ */
+
+ impl Solution {
+    pub fn rand10() -> i32 {
+        loop {
+            let i = rand7() - 1;
+            let j = rand7();
+            let x = i * 7 + j;
+            if x <= 40 {
+                return (x % 10) + 1;
+            }
+        }
+    }
+}