Fix typo in comment.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@345805 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Frontend/CompilerInstance.cpp

@@ -372,7 +372,7 @@ static void InitializeFileRemapping(DiagnosticsEngine &Diags,
 void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
   const PreprocessorOptions &PPOpts = getPreprocessorOpts();
 
-  // The module manager holds a reference to the old prepreocssor (if any).
+  // The module manager holds a reference to the old preprocessor (if any).
   ModuleManager.reset();
 
   // Create a PTH manager if we are using some form of a token cache.