fix path
diff --git a/tools/doxygen/Doxyfile.c++.internal b/tools/doxygen/Doxyfile.c++.internal
index c2dbfb6..7f24e84 100644
--- a/tools/doxygen/Doxyfile.c++.internal
+++ b/tools/doxygen/Doxyfile.c++.internal
@@ -766,11 +766,11 @@
include/grpc++/completion_queue.h \
include/grpc++/create_channel.h \
include/grpc++/create_channel_posix.h \
-include/grpc++/ext/health_check_service_interface.h \
include/grpc++/ext/health_check_service_server_builder_option.h \
include/grpc++/generic/async_generic_service.h \
include/grpc++/generic/generic_stub.h \
include/grpc++/grpc++.h \
+include/grpc++/health_check_service_interface.h \
include/grpc++/impl/call.h \
include/grpc++/impl/client_unary_call.h \
include/grpc++/impl/codegen/core_codegen.h \