[compare.type] Fix argument names invoking spec macro

Co-authored-by: Jonathan Wakely <[email protected]>

Author: AlisdairM

source/support.tex

@@ -5709,7 +5709,7 @@
 \pnum
 The name \tcode{type_order} denotes a \oldconcept{BinaryTypeTrait}\iref{meta.rqmts}
 with a base characteristic of
-\tcode{integral_constant<strong_ordering, \exposid{TYPE-ORDER}(X, Y)>}.
+\tcode{integral_constant<strong_ordering, \exposid{TYPE-ORDER}(T, U)>}.
 
 \pnum
 \recommended