Added an incrementing example to as->

I appologise if the formatting isn't as it should be. I tried finding an example of how it should be formatted but was suprised to find that map (https://github.com/arrdem/grimoire/blob/master/_includes/1.6.0/clojure.core/map/examples.md) doesn't show any examples even though they appear on the website http://grimoire.arrdem.com/1.6.0/clojure.core/map/
Merge pull request #40 from logaan/patch-1

Added an incrementing example to as->