Adding semicolon after declaration

Author: yarusome

learn/selectors/before.html

@@ -11,7 +11,7 @@
 
     <style class="editable">
     .box::before {
-        content: "This should show before the other content."
+        content: "This should show before the other content. ";
     }
 
     </style>
@@ -24,7 +24,7 @@
 
     <textarea class="playable playable-css" style="height: 80px;">
 .box::before {
-    content: "This should show before the other content."
+    content: "This should show before the other content. ";
 }   
     </textarea>
 
@@ -38,4 +38,4 @@
 </body>
 <script src="../playable.js"></script>
 
-</html>
+</html>