Escape more @ signs in Doxygen comments.

Doxygen treats "@command" the same as "\command" in a doc comment, so
whenever we talk about Objective-C things like "@interface" we have to
make sure to escape them.

Let's try to keep Clang -Wdocumentation-clean!

llvm-svn: 178603

clang/include/clang/AST/CommentCommandTraits.h

@@ -105,10 +105,10 @@ struct CommandInfo {
   unsigned IsFunctionDeclarationCommand : 1;
 
   /// \brief True if block command is further describing a container API; such
-  /// as @coclass, @classdesign, etc.
+  /// as \@coclass, \@classdesign, etc.
   unsigned IsRecordLikeDetailCommand : 1;
   
-  /// \brief True if block command is a container API; such as @interface.
+  /// \brief True if block command is a container API; such as \@interface.
   unsigned IsRecordLikeDeclarationCommand : 1;
   
   /// \brief True if this command is unknown.  This \c CommandInfo object was

clang/include/clang/AST/DeclBase.h

@@ -135,7 +135,7 @@ public:
     /// or member ends up here.
     IDNS_Ordinary            = 0x0020,
 
-    /// Objective C @protocol.
+    /// Objective C \@protocol.
     IDNS_ObjCProtocol        = 0x0040,
 
     /// This declaration is a friend function.  A friend function

clang/include/clang/AST/ExprObjC.h

@@ -417,9 +417,13 @@ public:
   child_range children() { return child_range(); }
 };
 
-/// ObjCProtocolExpr used for protocol expression in Objective-C.  This is used
-/// as: @protocol(foo), as in:
-///   obj conformsToProtocol:@protocol(foo)]
+/// ObjCProtocolExpr used for protocol expression in Objective-C.
+///
+/// This is used as: \@protocol(foo), as in:
+/// \code
+///   [obj conformsToProtocol:@protocol(foo)]
+/// \endcode
+///
 /// The return type is "Protocol*".
 class ObjCProtocolExpr : public Expr {
   ObjCProtocolDecl *TheProtocol;

clang/lib/Sema/SemaDecl.cpp

@@ -10807,8 +10807,8 @@ Decl *Sema::ActOnIvar(Scope *S,
 }
 
 /// ActOnLastBitfield - This routine handles synthesized bitfields rules for 
-/// class and class extensions. For every class @interface and class 
-/// extension @interface, if the last ivar is a bitfield of any type, 
+/// class and class extensions. For every class \@interface and class 
+/// extension \@interface, if the last ivar is a bitfield of any type, 
 /// then add an implicit `char :0` ivar to the end of that interface.
 void Sema::ActOnLastBitfield(SourceLocation DeclLoc,
                              SmallVectorImpl<Decl *> &AllIvarDecls) {