<script> tag between </head> and <body>

Under **Setting Up > Installing Pixi** is a block of code containing this:

```html
</head>
  <script src="pixi/pixi.min.js"></script>
<body>
```

But the script tag should be inside either the head or the body, so
```diff
- </head>
  <script src="pixi/pixi.min.js"></script>
+ </head>
<body>
```
