[Bug-mit-scheme] x11 graphics doesn't quite work.

[Gerald Jay Sussman]

By the way, the manual is not correct as to the name of the graphics
device type:


  From section 17.9.1: X Graphics Type in the current manual on gnu.org:

     A graphics device for X windows is created by passing the symbol
        x as the graphics device type name to make-graphics-device:

     (make-graphics-device 'x #!optional display geometry suppress-map?)


But the symbol with name "x" is not an accepted name, as seen below.
I suggest that both "x" and "x11" be acceptable, as well as the upper
case versions: "X" and "X11".


     Image saved on Sunday January 6, 2019 at 6:10:24 PM
       Release 10.1.4    || Microcode 15.3 || Runtime 15.7 || SF 4.41
       LIAR/x86-64 4.118 || SOS 1.8        || XML 1.0      || Edwin 3.117
       X11 1.2           || X11-Screen 1.0 || IMAIL 1.22

     (make-graphics-device 'x)
     ;Graphics type unknown: x
     ;Quit!

     (make-graphics-device 'x11)
     ;Value: #[graphics-device 12]