move files to subdir and add generated files
diff --git a/tools/doxygen/Doxyfile.c++.internal b/tools/doxygen/Doxyfile.c++.internal
index 5e3f226..c2dbfb6 100644
--- a/tools/doxygen/Doxyfile.c++.internal
+++ b/tools/doxygen/Doxyfile.c++.internal
@@ -855,8 +855,9 @@
src/cpp/server/secure_server_credentials.h \
src/cpp/client/create_channel_internal.h \
src/cpp/common/channel_filter.h \
-src/cpp/server/default_health_check_service.h \
src/cpp/server/dynamic_thread_pool.h \
+src/cpp/server/health/default_health_check_service.h \
+src/cpp/server/health/health.pb.h \
src/cpp/server/thread_pool_interface.h \
src/cpp/thread_manager/thread_manager.h \
src/cpp/client/insecure_credentials.cc \
@@ -883,10 +884,11 @@
src/cpp/common/version_cc.cc \
src/cpp/server/async_generic_service.cc \
src/cpp/server/create_default_thread_pool.cc \
-src/cpp/server/default_health_check_service.cc \
src/cpp/server/dynamic_thread_pool.cc \
-src/cpp/server/health_check_service.cc \
-src/cpp/server/health_check_service_server_builder_option.cc \
+src/cpp/server/health/default_health_check_service.cc \
+src/cpp/server/health/health.pb.c \
+src/cpp/server/health/health_check_service.cc \
+src/cpp/server/health/health_check_service_server_builder_option.cc \
src/cpp/server/server_builder.cc \
src/cpp/server/server_cc.cc \
src/cpp/server/server_context.cc \