sample.hgrc: hgk extension is now in hgext. Use churn as example for contrib.

contrib/sample.hgrc

@@ -46,7 +46,7 b''
 ### hgk - GUI repository browser
 ### hg help view
 
-# hgk = /home/user/hg/hg/contrib/hgk.py
+# hgext.hgk =
 
 ### mq - Mercurial patch queues
 ### hg help mq
@@ -63,6 +63,11 b''
 
 # hgext.patchbomb =
 
+### churn - create a graph showing who changed the most lines
+### hg help churn
+
+# hgext.churn = /home/user/hg/hg/contrib/churn.py
+
 ### win32text - line ending conversion filters for the Windows platform
 
 # hgext.win32text =