[project @ 2005-02-28 12:03:12 by simonmar]

The type variables in the types of wired-in entities were built using
mkVarOcc, which gives a variable name rather than a type variable
name.  Normally the compiler doesn't care, but when tidying types for
output to the user the tidier would consider a VarName as distinct
from a TvName, and not give them different print names.

This fix makes puts all the type variables in the TvName namespace.