fix doxygen brief in subzero header files

src/IceTargetLoweringX86BaseImpl.h

 //===- subzero/src/IceTargetLoweringX86BaseImpl.h - x86 lowering -*- C++ -*-==//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
-/// This file implements the TargetLoweringX86Base class, which consists almost
+/// \brief Implements the TargetLoweringX86Base class, which consists almost
 /// entirely of the lowering sequence for each high-level instruction.
 ///
 //===----------------------------------------------------------------------===//
 
 #ifndef SUBZERO_SRC_ICETARGETLOWERINGX86BASEIMPL_H
 #define SUBZERO_SRC_ICETARGETLOWERINGX86BASEIMPL_H
 
 #include "IceCfg.h"
 #include "IceCfgNode.h"
 #include "IceClFlags.h"
@@ skipping 6184 matching lines @@
   }
   // the offset is not eligible for blinding or pooling, return the original
   // mem operand
   return MemOperand;
 }
 
 } // end of namespace X86Internal
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERINGX86BASEIMPL_H