[plt-scheme] Doc bug: typo

Since it seems bugs.plt-scheme.org is down:
Just a typo in introduction of ffi manual:
"For example, ptr-equal? can never cause memry corruption or an
invalid memory access, so it is immediately available on import."

memry should be memory. :-)

Cheers,

-- 
Paulo Jorge Matos - pocm at soton.ac.uk
http://www.personal.soton.ac.uk/pocm
PhD Student @ ECS
University of Southampton, UK