Remove \brief commands from doxygen comments.

This is similar to the LLVM change https://reviews.llvm.org/D46290.

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

Differential Revision: https://reviews.llvm.org/D46320

llvm-svn: 331834
diff --git a/clang/lib/StaticAnalyzer/Frontend/ModelConsumer.cpp b/clang/lib/StaticAnalyzer/Frontend/ModelConsumer.cpp
index a65a5ee..60825ef 100644
--- a/clang/lib/StaticAnalyzer/Frontend/ModelConsumer.cpp
+++ b/clang/lib/StaticAnalyzer/Frontend/ModelConsumer.cpp
@@ -8,7 +8,7 @@
 //===----------------------------------------------------------------------===//
 ///
 /// \file
-/// \brief This file implements an ASTConsumer for consuming model files.
+/// This file implements an ASTConsumer for consuming model files.
 ///
 /// This ASTConsumer handles the AST of a parsed model file. All top level
 /// function definitions will be collected from that model file for later