Add missing apostrophe. It's been bugging me for years.

No really, years.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8566 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/CommandLine.cpp b/lib/Support/CommandLine.cpp
index 2d57abd..c0be0ec 100644
--- a/lib/Support/CommandLine.cpp
+++ b/lib/Support/CommandLine.cpp
@@ -400,7 +400,7 @@
     }
 
     if (Handler == 0) {
-      std::cerr << "Unknown command line argument '" << argv[i] << "'.  Try: "
+      std::cerr << "Unknown command line argument '" << argv[i] << "'.  Try: '"
                 << argv[0] << " --help'\n";
       ErrorParsing = true;
       continue;