[LLD] [test] Add a forgotten comment. NFC.

This was requested in https://reviews.llvm.org/D68014, but I forgot
to add it before pushing the commit.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@373145 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/ELF/undef.s b/test/ELF/undef.s
index 3d432b0..f16bd47 100644
--- a/test/ELF/undef.s
+++ b/test/ELF/undef.s
@@ -23,6 +23,8 @@
 # CHECK: error: undefined symbol: vtable for Foo
 # CHECK: the vtable symbol may be undefined because the class is missing its key function (see https://lld.llvm.org/missingkeyfunction)
 
+# Check that this symbol isn't demangled
+
 # CHECK: error: undefined symbol: __Z3fooi
 # CHECK: >>> referenced by undef.s
 # CHECK: >>>               {{.*}}:(.text+0x1A)