tweak Hall of Fame page

* clarify what the stats show
* link to the GitHub Pulse page, which is actually a lot better

Author: SethTisue

contribute/scala-fame.md

@@ -3,10 +3,17 @@ layout: page-full-width
 title: Scala Contributor Hall of Fame
 ---
 
-A big thank you to everyone who contributed to:
+A big thank you to everyone who has contributed over the years to:
  - [the Scala library and compiler](https://github.com/scala/scala/contributors)
  - [the Scala documentation website](https://github.com/scala/scala.github.com/contributors)
 
+What follows are the commit totals, to the 2.11.x branch of the scala/scala repo only,
+for last month.  (For a commit to be counted, it must have been both committed and merged
+in the same month.)
+
+For more a detailed view of recent activity, see the repo's
+[GitHub Pulse page](https://github.com/scala/scala/pulse/monthly).
+
 {% for data in site.categories.scala-fame-data limit:1 %}
   {% assign famedata = data %}
   {% include render-scala-fame.html %}