samplehgrcs: clarify which lines should be uncommented

The original wording has confused at least one person. Hopefully it's
clearer this way.

https://stackoverflow.com/questions/55288177/adding-hg-strip-to-hgrc-config-file

mercurial/ui.py

@@ -97,7 +97,7 b' username ='
 # paginate = never
 
 [extensions]
-# uncomment these lines to enable some popular extensions
+# uncomment the lines below to enable some popular extensions
 # (see 'hg help extensions' for more info)
 #
 # churn =
@@ -149,7 +149,7 b' b"""# example system-wide hg config (see'
 # paginate = never
 
 [extensions]
-# uncomment these lines to enable some popular extensions
+# uncomment the lines below to enable some popular extensions
 # (see 'hg help extensions' for more info)
 #
 # blackbox =