add link to docs

[waigani]

Try the following method.

In your pages.yml:

in pages:... section, compose link title as actual title|href (I found handy to mark external links with 🗗 Unicode character), for example - 'Google &#x1F5D7|http://www.google.com/': 'index.md'
(just pretend it's local file, it only must be existing md)
in extra_javascript:... section, declare file with following code:

var anchors = Array.from(document.getElementsByClassName("navbar-collapse")[0].getElementsByTagName("a"));
anchors.forEach(function(anchor) {
	var sep = anchor.innerText.indexOf("|");
	if (sep != -1) {
		anchor.href = anchor.innerText.substring(sep + 1, anchor.innerText.length);
		anchor.innerText = anchor.innerText.substring(0,sep);
	}
	if (anchor.innerText.indexOf("\uD83D\uDDD7") != -1) { // 🗗 = "new window" char, see http://www.fileformat.info/info/unicode/char/1f5d7/index.htm
		anchor.target = "_blank";
	}
});