More demonstrative code example (skills#64)

* demonstrative example 

Changed the example shown to demonstrate better how markdown formats (colours) the code block based on the given language, in this case javascript.

* Retained previous example

Based on feedback on pull request skills#64 from @cmwilson21 the example given in commit 784e639 should stay, but so should the original example.

Author: thomashudsonuk

.github/steps/3-add-a-code-example.md

@@ -10,7 +10,7 @@ _Great job adding an image to the file :tada:_
 
 In addition to code blocks, some code blocks should be rendered differently depending on the language, such as JavaScript or command-line text.
 
-### Example
+### Example 1
 
 <pre>
 ```
@@ -26,6 +26,20 @@ $ git init
 Initialized empty Git repository in /Users/skills/Projects/recipe-repository/.git/
 ```
 
+### Example 2
+
+<pre>
+``` javascript
+var myVar = "Hello, world!";
+```
+</pre>
+
+#### How it looks
+
+```javascript
+var myVar = "Hello, world!";
+```
+
 ### :keyboard: Activity: Adding a code example
 
 1. As you did before, edit the file in this pull request.