fix doxygen brief in subzero header files

src/IceConverter.cpp

 //===- subzero/src/IceConverter.cpp - Converts LLVM to Ice  ---------------===//
 //
 //                        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 LLVM to ICE converter.
+/// \brief Implements the LLVM to ICE converter.
 ///
 //===----------------------------------------------------------------------===//
 
 #include "IceConverter.h"
 
 #include "IceCfg.h"
 #include "IceCfgNode.h"
 #include "IceClFlags.h"
 #include "IceDefs.h"
 #include "IceGlobalContext.h"
@@ skipping 896 matching lines @@
       Ctx->pushTimer(TimerID, StackID);
     }
     LLVM2ICEFunctionConverter FunctionConverter(*this);
     FunctionConverter.convertFunction(&I);
     if (TimeThisFunction)
       Ctx->popTimer(TimerID, StackID);
   }
 }
 
 } // end of namespace Ice