Use sigPrec in more places in Convert and HsUtils
Trac #16183 (closed) was caused by TH conversion (in Convert
) not properly
inserting parentheses around occurrences of explicit signatures where
appropriate, such as in applications, function types, and type family
equations. Solution: use parenthesizeHsType sigPrec
in these
places. While I was in town, I also updated nlHsFunTy
to do the
same thing.