Revert r197043, not a good comment

llvm-svn: 197077

clang/include/clang/Lex/Pragma.h

@@ -28,12 +28,6 @@ namespace clang {
   /**
    * \brief Describes how the pragma was introduced, e.g., with \#pragma,
    * _Pragma, or __pragma.
-   *
-   * This is a callback and there is code outside of clang using it.
-   *
-   * The source location passed down together with the introducer kind is
-   * the one of the token *following* the introducer, so it would not be
-   * immediate for clients to re-lex to see which introducer it was.
    */
   enum PragmaIntroducerKind {
     /**