Fix Ord codegen to use other < self in reverse branch (#170)

The generated `Ord::cmp` for method-based `operator<` used
`other.<op>(other)` in its second branch, which can never evaluate true
and therefore suppresses `Ordering::Greater`. This change aligns that
branch with the intended reverse comparison (`other.<op>(self)`),
matching existing model-specific behavior.

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

Author: Copilot

cpp2rust/converter/converter.cpp

@@ -3722,7 +3722,7 @@ void Converter::ConvertOrdAndPartialOrdTraits(const clang::CXXRecordDecl *decl,
   case clang::OO_Less:
     if (clang::isa<clang::CXXMethodDecl>(op)) {
       first_branch = std::format("self.{}(other)", GetOverloadedOperator(op));
-      second_branch = std::format("other.{}(other)", GetOverloadedOperator(op));
+      second_branch = std::format("other.{}(self)", GetOverloadedOperator(op));
     } else {
       first_branch = std::format("{}(self, other)", GetOverloadedOperator(op));
       second_branch = std::format("{}(other, self)", GetOverloadedOperator(op));