updated instructions for clarity

Author: UmiKami

exercises/04-Class-Selector/README.es.md

@@ -18,6 +18,6 @@ Usa la propiedad `class` del elemento HTML para seleccionarlo. Las reglas de est
 ## 📝 Instrucciones:
 
 En este momento hay una clase seleccionada en el CSS llamada
-`.b-blue`.
+`b-blue`.
 
 Por favor aplica la clase a ambas etiquetas HTML `<p>`.

exercises/04-Class-Selector/README.md

@@ -22,7 +22,7 @@ Use the class property of the HTML element to select it. Styling rules will appl
 
 ## 📝 Instructions:
 
-Right now there is a class selected on the CSS that is called `.b-blue`. 
+Right now there is a class selected on the CSS that is called `b-blue`. 
 
 Please apply that class to both of the HTML `<p>` tags.