2016/applicative: add link to YouTube recording

Browsing through the slides today, I did a quick search and found the link
to the recording of Sameer Ajmani's talk at ACM Applicative on June 1, 2016.
This CL updates the "we'll add a link when the video is available" to the
link because, hey, it's available!

Great talk, Sameer.

Change-Id: Ia0bb0c938f8f38e52ef928185a9b2c4adf747853
Reviewed-on: https://go-review.googlesource.com/24866
Reviewed-by: Sameer Ajmani <sameer@golang.org>

2016/applicative.slide

diff --git a/2016/applicative.slide b/2016/applicative.slide
index 4f6a761..54d8657 100644
--- a/2016/applicative.slide
+++ b/2016/applicative.slide
@@ -10,7 +10,7 @@
 
 This talk was presented at the [[http://applicative.acm.org/][ACM Applicative]] conference in New York City on June 1, 2016.
 
-(We'll link the video here when it's ready.)
+.link https://www.youtube.com/watch?v=5bYO60-qYOI Watch the talk on YouTube
 
 * Outline