Fix formatting of macros that take types.

Fix formatting of macros that take types.

Previously, we would assume that a macro like IsA() in the following
example was a cast just because it mentions a known type between parens,
and that messed up the formatting of any binary operator that followed:

       if (IsA(outer_path, UniquePath) ||path->skip_mark_restore)

This change errs on the side of assuming that function-like macros are
similar to sizeof() and offsetof(), so that operators are formatted
correctly:

       if (IsA(outer_path, UniquePath) || path->skip_mark_restore)

Thomas Munro

Discussion: https://postgr.es/m/20200114221814.GA19630@alvherre.pgsql