Added yaml menu example, matching with existing toml example. Also added link to sitewide config page.
## Adding (non-content) entries to a menu
You can also add entries to menus that aren’t attached to a piece of
-content. This takes place in the site wide config file.
+content. This takes place in the site wide [config file](http://hugo.spf13.com/overview/configuration).
Here’s an example (in toml):
pre = "<i class='fa fa-road'></i>"
weight = -100
+Here’s an example (in yaml):
+
+ ---
+ menu:
+ main:
+ - Name: "about hugo"
+ Pre: "<i class='fa fa-heart'></i>"
+ Weight: -110
+ Identifier: "about"
+ - Name: "getting started"
+ Pre: "<i class='fa fa-road'></i>"
+ Weight: -100
+ ---
+
## Nesting
All nesting of content is done via the `parent` field.