[cmp.categories.pre] Remove unused enumerators

Fixes #3541.

Author: CaseyCarter

source/support.tex

@@ -4076,8 +4076,7 @@
 from one of the following exposition-only enumerations:
 
 \begin{codeblock}
-enum class @\placeholdernc{eq}@ { @\placeholdernc{equal}@ = 0, @\placeholdernc{equivalent}@ = @\placeholdernc{equal}@,
-                @\placeholdernc{nonequal}@ = 1, @\placeholdernc{nonequivalent}@ = @\placeholdernc{nonequal}@ };   // \expos
+enum class @\placeholdernc{eq}@ { @\placeholdernc{equal}@ = 0, @\placeholdernc{equivalent}@ = @\placeholdernc{equal}@ };            // \expos
 enum class @\placeholdernc{ord}@ { @\placeholdernc{less}@ = -1, @\placeholdernc{greater}@ = 1 };                  // \expos
 enum class @\placeholdernc{ncmp}@ { @\placeholdernc{unordered}@ = -127 };                       // \expos
 \end{codeblock}