Update article.md (#1402)

Update article.md

Author: lex111

1-js/09-classes/01-class/article.md

@@ -142,7 +142,7 @@ user.sayHi();
 
 The result of this definition is about the same. So, there are indeed reasons why `class` can be considered a syntax sugar to define a constructor together with its prototype methods.
 
-Although, there are important differences.
+Still, there are important differences.
 
 1. First, a function created by `class` is labelled by a special internal property `[[FunctionKind]]:"classConstructor"`. So it's not entirely the same as creating it manually.