fix doxygen brief in subzero header files

src/IceTargetLowering.h

 //===- subzero/src/IceTargetLowering.h - Lowering interface -----*- 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 declares the TargetLowering, LoweringContext, and
-/// TargetDataLowering classes. TargetLowering is an abstract class used to
-/// drive the translation/lowering process. LoweringContext maintains a context
-/// for lowering each instruction, offering conveniences such as iterating over
-/// non-deleted instructions. TargetDataLowering is an abstract class used to
-/// drive the lowering/emission of global initializers, external global
-/// declarations, and internal constant pools.
+/// \brief Declares the TargetLowering, LoweringContext, and TargetDataLowering
+/// classes.
+///
+/// TargetLowering is an abstract class used to drive the translation/lowering
+/// process. LoweringContext maintains a context for lowering each instruction,
+/// offering conveniences such as iterating over non-deleted instructions.
+/// TargetDataLowering is an abstract class used to drive the lowering/emission
+/// of global initializers, external global declarations, and internal constant
+/// pools.
 ///
 //===----------------------------------------------------------------------===//
 
 #ifndef SUBZERO_SRC_ICETARGETLOWERING_H
 #define SUBZERO_SRC_ICETARGETLOWERING_H
 
 #include "IceDefs.h"
 #include "IceInst.h" // for the names of the Inst subtypes
 #include "IceOperand.h"
 #include "IceTypes.h"
@@ skipping 440 matching lines @@
   virtual void lower() {}
 
 protected:
   explicit TargetHeaderLowering(GlobalContext *Ctx) : Ctx(Ctx) {}
   GlobalContext *Ctx;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICETARGETLOWERING_H