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/IR/DiagnosticHandler.cpp b/llvm/lib/IR/DiagnosticHandler.cpp
index fb1ac43..8f972785 100644
--- a/llvm/lib/IR/DiagnosticHandler.cpp
+++ b/llvm/lib/IR/DiagnosticHandler.cpp
@@ -17,7 +17,7 @@
 
 namespace {
 
-/// \brief Regular expression corresponding to the value given in one of the
+/// Regular expression corresponding to the value given in one of the
 /// -pass-remarks* command line flags. Passes whose name matches this regexp
 /// will emit a diagnostic when calling the associated diagnostic function
 /// (emitOptimizationRemark, emitOptimizationRemarkMissed or