fix doxygen brief in subzero header files

src/IceInst.h

 //===- subzero/src/IceInst.h - High-level instructions ----------*- 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 Inst class and its target-independent
-/// subclasses, which represent the high-level Vanilla ICE instructions
-/// and map roughly 1:1 to LLVM instructions.
+/// \brief Declares the Inst class and its target-independent subclasses.
+///
+/// These represent the high-level Vanilla ICE instructions and map roughly 1:1
+/// to LLVM instructions.
 ///
 //===----------------------------------------------------------------------===//
 
 #ifndef SUBZERO_SRC_ICEINST_H
 #define SUBZERO_SRC_ICEINST_H
 
 #include "IceCfg.h"
 #include "IceDefs.h"
 #include "IceInst.def"
 #include "IceIntrinsics.h"
@@ skipping 961 matching lines @@
   static void noteHead(Ice::Inst *, Ice::Inst *) {}
   void deleteNode(Ice::Inst *) {}
 
 private:
   mutable ilist_half_node<Ice::Inst> Sentinel;
 };
 
 } // end of namespace llvm
 
 #endif // SUBZERO_SRC_ICEINST_H