Clarify test comment

Author: thurstond

clang/test/CodeGen/ubsan-trap-merge.c

@@ -1,6 +1,6 @@
 // NOTE: Assertions have mostly been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 5
 // The most important assertion is the attributes at the end of the file, which
-// shows that ubsan attaches 'nomerge' to each ubsantrap intrinsic.
+// shows that -ubsan-unique-traps attaches 'nomerge' to each ubsantrap intrinsic.
 //
 // RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm -fsanitize=signed-integer-overflow -fsanitize-trap=signed-integer-overflow -O3 -mllvm -ubsan-unique-traps %s -o - \
 // RUN:     | FileCheck %s