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/Lex/PreprocessingRecord.cpp b/clang/lib/Lex/PreprocessingRecord.cpp
index cd4a63f..5537479 100644
--- a/clang/lib/Lex/PreprocessingRecord.cpp
+++ b/clang/lib/Lex/PreprocessingRecord.cpp
@@ -54,7 +54,7 @@
 
 PreprocessingRecord::PreprocessingRecord(SourceManager &SM) : SourceMgr(SM) {}
 
-/// \brief Returns a pair of [Begin, End) iterators of preprocessed entities
+/// Returns a pair of [Begin, End) iterators of preprocessed entities
 /// that source range \p Range encompasses.
 llvm::iterator_range<PreprocessingRecord::iterator>
 PreprocessingRecord::getPreprocessedEntitiesInRange(SourceRange Range) {
@@ -88,7 +88,7 @@
   return SM.isInFileID(SM.getFileLoc(Loc), FID);
 }
 
-/// \brief Returns true if the preprocessed entity that \arg PPEI iterator
+/// Returns true if the preprocessed entity that \arg PPEI iterator
 /// points to is coming from the file \arg FID.
 ///
 /// Can be used to avoid implicit deserializations of preallocated
@@ -132,7 +132,7 @@
                                         FID, SourceMgr);
 }
 
-/// \brief Returns a pair of [Begin, End) iterators of preprocessed entities
+/// Returns a pair of [Begin, End) iterators of preprocessed entities
 /// that source range \arg R encompasses.
 std::pair<int, int>
 PreprocessingRecord::getPreprocessedEntitiesInRangeSlow(SourceRange Range) {
@@ -351,7 +351,7 @@
   MacroDefinitions[Macro] = Def;
 }
 
-/// \brief Retrieve the preprocessed entity at the given ID.
+/// Retrieve the preprocessed entity at the given ID.
 PreprocessedEntity *PreprocessingRecord::getPreprocessedEntity(PPEntityID PPID){
   if (PPID.ID < 0) {
     unsigned Index = -PPID.ID - 1;
@@ -368,7 +368,7 @@
   return PreprocessedEntities[Index];
 }
 
-/// \brief Retrieve the loaded preprocessed entity at the given index.
+/// Retrieve the loaded preprocessed entity at the given index.
 PreprocessedEntity *
 PreprocessingRecord::getLoadedPreprocessedEntity(unsigned Index) {
   assert(Index < LoadedPreprocessedEntities.size() &&