fix doxygen brief in subzero header files

src/IceTargetLoweringMIPS32.h

Index: src/IceTargetLoweringMIPS32.h
diff --git a/src/IceTargetLoweringMIPS32.h b/src/IceTargetLoweringMIPS32.h
index 387ec2ef29a3ac4ed616ae1c2272d3c00ba0d2bc..bf96661d5241378c0cae27aa26d73b6aeaa4e912 100644
--- a/src/IceTargetLoweringMIPS32.h
+++ b/src/IceTargetLoweringMIPS32.h
@@ -8,7 +8,7 @@
 //===----------------------------------------------------------------------===//
 ///
 /// \file
-/// This file declares the TargetLoweringMIPS32 class, which implements the
+/// \brief Declares the TargetLoweringMIPS32 class, which implements the
 /// TargetLowering interface for the MIPS 32-bit architecture.
 ///
 //===----------------------------------------------------------------------===//