bug#23355: list-buffers should also show directories using ~

[積丹尼 Dan Jacobson]

C-x C-b runs the command list-buffers, which is an interactive
compiled Lisp function in `buff-menu.el'.

It seems to me it shows things inconsistently,

    minimal_data_usage/Makefile              1664 GNUmakefile      
~/android/minimal_data_usage/Makefile
 %  minimal_data_usage                        598 Dired by date    
/home/jidanni/android/minimal_data_usage/
    s.cgi                                    1088 Shell-script[... 
~/android/minimal_data_usage/s.cgi
    other/Makefile                            494 GNUmakefile      
~/facebook/messages/other/Makefile
 %  other                                     263 Dired by name    
/home/jidanni/facebook/messages/other/

Directories are not shown with ~/, only files are.

emacs-version "24.5.1"