Annotate dump() methods with LLVM_DUMP_METHOD, addressing Richard Smith r259192 post commit comment.

llvm-svn: 259232
diff --git a/clang/lib/AST/DeclarationName.cpp b/clang/lib/AST/DeclarationName.cpp
index b2f2727..8322b60 100644
--- a/clang/lib/AST/DeclarationName.cpp
+++ b/clang/lib/AST/DeclarationName.cpp
@@ -333,7 +333,7 @@
   return DeclarationName(Ptr);
 }
 
-void DeclarationName::dump() const {
+LLVM_DUMP_METHOD void DeclarationName::dump() const {
   llvm::errs() << *this << '\n';
 }