split iterator into its own file
diff --git a/tools/doxygen/Doxyfile.c++ b/tools/doxygen/Doxyfile.c++
index feb7ad8..3f33710 100644
--- a/tools/doxygen/Doxyfile.c++
+++ b/tools/doxygen/Doxyfile.c++
@@ -763,6 +763,7 @@
 INPUT                  = include/grpc++/async_generic_service.h \
 include/grpc++/async_unary_call.h \
 include/grpc++/auth_context.h \
+include/grpc++/auth_property_iterator.h \
 include/grpc++/byte_buffer.h \
 include/grpc++/channel_arguments.h \
 include/grpc++/channel_interface.h \