docs(fibonacci2): correct typo

This has a deliberate error for code-review training

subjects/fibonacci2/README.md

@@ -13,7 +13,7 @@ This function receives a number `n` and returns the `n`th number in the fibonacc
 
 The Fibonacci Series starts like this: 0, 1, 1, 2, 3, 5, 8, 13 etc...
 
-### Usage
+### Usag
 
 Here is a possible test for your function:
 
@@ -21,7 +21,7 @@ Here is a possible test for your function:
 use fibonacci2::fibonacci;
 
 fn main() {
-    println!("The element in the position {} in fibonacci series is {}",2,  fibonacci(2));
+    println!("The element in the position {} in fibonacci series is {}",2, fibonacci(2));
     println!("The element in the position {} in fibonacci series is {}",4, fibonacci(4));
     println!("The element in the position {} in fibonacci series is {}",22, fibonacci(22));
     println!("The element in the position {} in fibonacci series is {}", 20, fibonacci(20));