Update article.md

Author: leviding

1-js/02-first-steps/08-operators/article.md

@@ -63,8 +63,8 @@ In school maths, we write that as a<sup>b</sup>.
 For instance:
 
 ```js run
-alert( 2 ** 2 ); // 2² = 4  
-alert( 2 ** 3 ); // 2³ = 8 
+alert( 2 ** 2 ); // 2² = 4
+alert( 2 ** 3 ); // 2³ = 8
 alert( 2 ** 4 ); // 2⁴ = 16
 ```