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/Serialization/ASTWriterStmt.cpp b/clang/lib/Serialization/ASTWriterStmt.cpp
index 5d288f9..665b879 100644
--- a/clang/lib/Serialization/ASTWriterStmt.cpp
+++ b/clang/lib/Serialization/ASTWriterStmt.cpp
@@ -8,7 +8,7 @@
 //===----------------------------------------------------------------------===//
 ///
 /// \file
-/// \brief Implements serialization for Statements and Expressions.
+/// Implements serialization for Statements and Expressions.
 ///
 //===----------------------------------------------------------------------===//
 
@@ -2677,7 +2677,7 @@
   SwitchCaseIDs.clear();
 }
 
-/// \brief Write the given substatement or subexpression to the
+/// Write the given substatement or subexpression to the
 /// bitstream.
 void ASTWriter::WriteSubStmt(Stmt *S) {
   RecordData Record;
@@ -2721,7 +2721,7 @@
   SubStmtEntries[S] = Offset;
 }
 
-/// \brief Flush all of the statements that have been added to the
+/// Flush all of the statements that have been added to the
 /// queue via AddStmt().
 void ASTRecordWriter::FlushStmts() {
   // We expect to be the only consumer of the two temporary statement maps,