closes#1152.
related to #1136 but `? File.exists?` is still not showing me documentation.
thanks to @yui-knk for finding the bug & providing a solution.
https://github.com/johnny5-/pry-bond project adds the enable-bond! and disable-bond! commands,
as well as other features, that enhance the pry&bond experience and make it easier to use and
setup without a manual effort.
see #1165closes#1160