fix doxygen brief in subzero header files

src/IceOperand.cpp

 //===- subzero/src/IceOperand.cpp - High-level operand 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 Operand class and its target-independent
-/// subclasses, primarily for the methods of the Variable class.
+/// \brief Implements the Operand class and its target-independent subclasses,
+/// primarily for the methods of the Variable class.
 ///
 //===----------------------------------------------------------------------===//
 
 #include "IceOperand.h"
 
 #include "IceCfg.h"
 #include "IceCfgNode.h"
 #include "IceInst.h"
 #include "IceInstVarIter.h"
 #include "IceTargetLowering.h" // dumping stack/frame pointer register
@@ skipping 524 matching lines @@
   if (getType() != IceType_i32 && getType() != IceType_i16 &&
       getType() != IceType_i8)
     return false;
   // The Following checks if the signed representation of Value is between
   // -Threshold/2 and +Threshold/2
   bool largerThanThreshold = Threshold / 2 + Value >= Threshold;
   return largerThanThreshold;
 }
 
 } // end of namespace Ice