Remove \brief commands from doxygen comments.

We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.

Patch produced by

  for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done

Differential Revision: https://reviews.llvm.org/D46290

llvm-svn: 331272
diff --git a/llvm/lib/Transforms/Instrumentation/CFGMST.h b/llvm/lib/Transforms/Instrumentation/CFGMST.h
index 075e567..54a36eb 100644
--- a/llvm/lib/Transforms/Instrumentation/CFGMST.h
+++ b/llvm/lib/Transforms/Instrumentation/CFGMST.h
@@ -31,7 +31,7 @@
 
 namespace llvm {
 
-/// \brief An union-find based Minimum Spanning Tree for CFG
+/// An union-find based Minimum Spanning Tree for CFG
 ///
 /// Implements a Union-find algorithm to compute Minimum Spanning Tree
 /// for a given CFG.