config: drop pager from the recommended extension stable

config: drop pager from the recommended extension

The extension is deprecated, we should having exposing it to users.

--- a/mercurial/ui.py	Mon May 01 15:51:47 2017 +0200
+++ b/mercurial/ui.py	Mon May 01 15:51:57 2017 +0200
@@ -60,7 +60,7 @@
 # (see 'hg help extensions' for more info)
 #
 # churn =
-# pager =""",
+""",
 
     'cloned':
 """# example repository config (see 'hg help config' for more info)
@@ -109,7 +109,7 @@
 #
 # blackbox =
 # churn =
-# pager =""",
+""",
 }