Documentation cleanup: escape # characters in Doxygen comments as needed.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@158970 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/PPLexerChange.cpp b/lib/Lex/PPLexerChange.cpp
index b6689df..e824320 100644
--- a/lib/Lex/PPLexerChange.cpp
+++ b/lib/Lex/PPLexerChange.cpp
@@ -31,7 +31,7 @@
 //===----------------------------------------------------------------------===//
 
 /// isInPrimaryFile - Return true if we're in the top-level file, not in a
-/// #include.  This looks through macro expansions and active _Pragma lexers.
+/// \#include.  This looks through macro expansions and active _Pragma lexers.
 bool Preprocessor::isInPrimaryFile() const {
   if (IsFileLexer())
     return IncludeMacroStack.empty();