Update article.md

Author: maurodibert

1-js/09-classes/06-instanceof/article.md

@@ -46,7 +46,7 @@ alert( arr instanceof Object ); // true
 
 Please note that `arr` also belongs to the `Object` class. That's because `Array` prototypally inherits from `Object`.
 
-The `instanceof` operator examines the prototype chain for the check, but we can set a custom logic the static method `Symbol.hasInstance`.
+The `instanceof` operator examines the prototype chain for the check, but we can set a custom logic in the static method `Symbol.hasInstance`.
 
 The algorithm of `obj instanceof Class` works roughly as follows: