scribble/base: fix `verbatim`

Typewriter font got lost in generalization to support non-string
arguments.
annotate some primitives as "immediate"

This annotation is useful mainly for functions that might be called
frequently from JIT-generated code.
make `random` slightly faster on 64-bit machines in integer mode

Exploit the fact that a 32-bit range fits in a fixnum.
racket/gui cocoa: fix 'resize-border style for `dialog%`

Also, fix documentation to reflect windo styles of different Mac OS X
versions.