[R6RS] a typo and some lexical issues

[William D Clinger]

Mike wrote:
> My gut feeling is no, but I'm unsure what the rationale for that would
> be.

I'd prefer just to go with #vu8(...).  In fact, I was
surprised by your decision to accept #T etc, but the
rationale for that is backward compatibility.  There
is no such issue for #vu8(...), and the absence of a
rationale for allowing #VU8(...) etc counts as a
rationale for not allowing it.

Will