[plt-scheme] typo in pre-release quick introduction

[Eli Barzilay]

On Feb  2, David Vanderson wrote:
> Hello,
> 
> Please let me know if this isn't the right place to report this.

Thanks -- I've comitted the fix.

-- 
          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                  http://www.barzilay.org/                 Maze is Life!