fix doxygen brief in subzero header files

src/IceInstMIPS32.cpp

 //===- subzero/src/IceInstMips32.cpp - Mips32 instruction implementation --===//
 //
 //                        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 InstMips32 and OperandMips32 classes, primarily the
+/// \brief Implements the InstMips32 and OperandMips32 classes, primarily the
 /// constructors and the dump()/emit() methods.
 ///
 //===----------------------------------------------------------------------===//
 #include "IceAssemblerMIPS32.h"
 #include "IceCfg.h"
 #include "IceCfgNode.h"
 #include "IceInst.h"
 #include "IceInstMIPS32.h"
 #include "IceOperand.h"
 #include "IceRegistersMIPS32.h"
@@ skipping 246 matching lines @@
       Str << "move";
   }
 
   Str << "\t";
   getDest()->emit(Func);
   Str << ", ";
   getSrc(0)->emit(Func);
 }
 
 } // end of namespace Ice