Update default.html

Author: thomasleplus

_layouts/default.html

@@ -29,6 +29,8 @@ <h2>{{ site.description | default: site.github.project_tagline }}</h2>
       <section id="editor">
         <hr>
         <h3>Playground</h3>
+	Modify the name and the source code below and the bookmarklet
+	in the "Result" section will update to reflect it in real-time.
 	<h4>Name</h4>
 	<input class="container" style="background: rgba(0,0,0,0.9); border: 1px solid rgba(255,255,255,0.15); padding: 10px; font-size: 16px; color: #d0d0d0; border-radius: 2px; word-wrap: normal; overflow: scroll;" type="text" id="mininame" name="mininame" value="Hello, world!">
 	<h4 style="margin-top: 10px;">Source code</h4>