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/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index e3ea1bf..b64a5d5 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -685,7 +685,7 @@
   return GetDefaultCXXStdlibType();
 }
 
-/// \brief Utility function to add a system include directory to CC1 arguments.
+/// Utility function to add a system include directory to CC1 arguments.
 /*static*/ void ToolChain::addSystemInclude(const ArgList &DriverArgs,
                                             ArgStringList &CC1Args,
                                             const Twine &Path) {
@@ -693,7 +693,7 @@
   CC1Args.push_back(DriverArgs.MakeArgString(Path));
 }
 
-/// \brief Utility function to add a system include directory with extern "C"
+/// Utility function to add a system include directory with extern "C"
 /// semantics to CC1 arguments.
 ///
 /// Note that this should be used rarely, and only for directories that
@@ -715,7 +715,7 @@
     addExternCSystemInclude(DriverArgs, CC1Args, Path);
 }
 
-/// \brief Utility function to add a list of system include directories to CC1.
+/// Utility function to add a list of system include directories to CC1.
 /*static*/ void ToolChain::addSystemIncludes(const ArgList &DriverArgs,
                                              ArgStringList &CC1Args,
                                              ArrayRef<StringRef> Paths) {