Fix keyseq specification in Bash (#426)

The current way of setting the keyseq as « bind "'\C-r': '...'" ≫
appears to be working as expected, but this is accidental.  This is
not the format that Readline supports; the keyseq cannot be enclosed
in single quotes.  This is now working because of Readline's loose
treatment of the keyseqs, but this will easily be broken with a
slightly different key.

mcfly.bash

@@ -119,9 +119,9 @@ function mcfly_initialize {
       #      which should be the commented-out search from step #1. It will then remove that line from the history file and
       #      render the search UI pre-filled with it.
       if set -o | grep "vi " | grep -q on; then
-        bind "'\C-r': '\e0i#mcfly: \e\C-m mcfly search\C-m'"
+        bind '"\C-r": "\e0i#mcfly: \e\C-m mcfly search\C-m"'
       else
-        bind "'\C-r': '\C-amcfly: \e# mcfly search\C-m'"
+        bind '"\C-r": "\C-amcfly: \e# mcfly search\C-m"'
       fi
     fi
   fi