Change script injection snippet version and format

[jrhorn424]

var script = document.createElement('script');script.src = "https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js";document.getElementsByTagName('head')[0].appendChild(script);

This is an in-line code block, and should be a fenced code block.

Also, the version should be updated.

[gaand]

This happens on github:

VM155:1 Refused to load the script 'https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js' because it violates the following Content Security Policy directive: "script-src assets-cdn.github.com".

So we might want to mention it.

[payne-chris-r]

See #31

[gaand]

See my comment on #31