Corrected some comment typos; NFC.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@305385 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Frontend/FrontendOptions.h

@@ -317,8 +317,8 @@ public:
   /// \brief Auxiliary triple for CUDA compilation.
   std::string AuxTriple;
 
-  /// \brief If non-empty, search the pch input file as it was a header
-  // included by this file.
+  /// \brief If non-empty, search the pch input file as if it was a header
+  /// included by this file.
   std::string FindPchSource;
 
   /// Filename to write statistics to.