fix doxygen brief in subzero header files

src/IceLiveness.h

 //===- subzero/src/IceLiveness.h - Liveness analysis ------------*- 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 Liveness and LivenessNode classes, which are used for
-/// liveness analysis. The node-specific information tracked for each Variable
-/// includes whether it is live on entry, whether it is live on exit, the
-/// instruction number that starts its live range, and the instruction number
-/// that ends its live range. At the Cfg level, the actual live intervals are
-/// recorded.
+/// \brief Declares the Liveness and LivenessNode classes, which are used for
+/// liveness analysis.
+///
+/// The node-specific information tracked for each Variable includes whether it
+/// is live on entry, whether it is live on exit, the instruction number that
+/// starts its live range, and the instruction number that ends its live range.
+/// At the Cfg level, the actual live intervals are recorded.
 ///
 //===----------------------------------------------------------------------===//
 
 #ifndef SUBZERO_SRC_ICELIVENESS_H
 #define SUBZERO_SRC_ICELIVENESS_H
 
 #include "IceCfgNode.h"
 #include "IceDefs.h"
 #include "IceTypes.h"
 
@@ skipping 88 matching lines @@
   /// variables.
   CfgVector<Variable *> LiveToVarMap;
   /// RangeMask[Variable::Number] indicates whether we want to track that
   /// Variable's live range.
   llvm::BitVector RangeMask;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICELIVENESS_H