Update clang to r339409.

Change-Id: I800772d2d838223be1f6b40d490c4591b937fca2
diff --git a/linux-x64/clang/include/llvm/ADT/APFloat.h b/linux-x64/clang/include/llvm/ADT/APFloat.h
index 6c0b6ae..5c59af4 100644
--- a/linux-x64/clang/include/llvm/ADT/APFloat.h
+++ b/linux-x64/clang/include/llvm/ADT/APFloat.h
@@ -1215,7 +1215,7 @@
   return X;
 }
 
-/// \brief Returns the negated value of the argument.
+/// Returns the negated value of the argument.
 inline APFloat neg(APFloat X) {
   X.changeSign();
   return X;