Update references from pryrepl.org to pry.github.io

lib/pry/cli.rb

@@ -122,7 +122,7 @@ Pry::CLI.add_options do
   banner(
     "Usage: pry [OPTIONS]\n" \
     "Start a Pry session.\n" \
-    "See http://pryrepl.org/ for more information.\n" \
+    "See http://pry.github.io/ for more information.\n" \
     "Copyright (c) 2016 John Mair (banisterfiend)" \
   )
 

lib/pry/pry_instance.rb

@@ -20,7 +20,7 @@ require 'ostruct'
 # This will show a list of available commands and their usage. For more
 # information about Pry you can refer to the following resources:
 #
-# * http://pryrepl.org/
+# * https://pry.github.io
 # * https://github.com/pry/pry
 # * the IRC channel, which is #pry on the Freenode network
 #