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/CodeGen/CGObjC.cpp b/clang/lib/CodeGen/CGObjC.cpp
index b156737..81c1201 100644
--- a/clang/lib/CodeGen/CGObjC.cpp
+++ b/clang/lib/CodeGen/CGObjC.cpp
@@ -259,7 +259,7 @@
   return CGM.getObjCRuntime().GenerateProtocolRef(*this, E->getProtocol());
 }
 
-/// \brief Adjust the type of an Objective-C object that doesn't match up due
+/// Adjust the type of an Objective-C object that doesn't match up due
 /// to type erasure at various points, e.g., related result types or the use
 /// of parameterized classes.
 static RValue AdjustObjCObjectType(CodeGenFunction &CGF, QualType ExpT,
@@ -803,7 +803,7 @@
   Kind = Native;
 }
 
-/// \brief Generate an Objective-C property getter function.
+/// Generate an Objective-C property getter function.
 ///
 /// The given Decl must be an ObjCImplementationDecl. \@synthesize
 /// is illegal within a category.
@@ -1336,7 +1336,7 @@
   EmitStmt(&assign);
 }
 
-/// \brief Generate an Objective-C property setter function.
+/// Generate an Objective-C property setter function.
 ///
 /// The given Decl must be an ObjCImplementationDecl. \@synthesize
 /// is illegal within a category.