fix doxygen brief in subzero header files

src/IceInstX8632.cpp

Index: src/IceInstX8632.cpp
diff --git a/src/IceInstX8632.cpp b/src/IceInstX8632.cpp
index 7c9e8551c2d62d2405a31b954ed131b62dd0fb1b..446651faf6d3342ad57c3fd5ee152162e49613f7 100644
--- a/src/IceInstX8632.cpp
+++ b/src/IceInstX8632.cpp
@@ -8,11 +8,11 @@
 //===----------------------------------------------------------------------===//
 ///
 /// \file
-/// This file defines X8632 specific data related to X8632 Instructions and
-/// Instruction traits. These are declared in the IceTargetLoweringX8632Traits.h
-/// header file.
+/// \brief Defines X8632 specific data related to X8632 Instructions and
+/// Instruction traits.
 ///
-/// This file also defines X8632 operand specific methods (dump and emit.)
+/// These are declared in the IceTargetLoweringX8632Traits.h header file. This
+/// file also defines X8632 operand specific methods (dump and emit.)
 ///
 //===----------------------------------------------------------------------===//
 #include "IceInstX8632.h"