Fix errors from tools/buildgen/generate_projects.sh

tools/doxygen/Doxyfile.c++

@@ -936,6 +936,7 @@ include/grpcpp/generic/async_generic_service.h \
 include/grpcpp/generic/generic_stub.h \
 include/grpcpp/grpcpp.h \
 include/grpcpp/health_check_service_interface.h \
+include/grpcpp/health_check_service_interface_impl.h \
 include/grpcpp/impl/call.h \
 include/grpcpp/impl/channel_argument_option.h \
 include/grpcpp/impl/client_unary_call.h \

tools/doxygen/Doxyfile.c++.internal

@@ -937,6 +937,7 @@ include/grpcpp/generic/async_generic_service.h \
 include/grpcpp/generic/generic_stub.h \
 include/grpcpp/grpcpp.h \
 include/grpcpp/health_check_service_interface.h \
+include/grpcpp/health_check_service_interface_impl.h \
 include/grpcpp/impl/call.h \
 include/grpcpp/impl/channel_argument_option.h \
 include/grpcpp/impl/client_unary_call.h \

tools/run_tests/generated/sources_and_headers.json

@@ -10069,6 +10069,7 @@
       "include/grpcpp/generic/generic_stub.h", 
       "include/grpcpp/grpcpp.h", 
       "include/grpcpp/health_check_service_interface.h", 
+      "include/grpcpp/health_check_service_interface_impl.h", 
       "include/grpcpp/impl/call.h", 
       "include/grpcpp/impl/channel_argument_option.h", 
       "include/grpcpp/impl/client_unary_call.h", 
@@ -10178,6 +10179,7 @@
       "include/grpcpp/generic/generic_stub.h", 
       "include/grpcpp/grpcpp.h", 
       "include/grpcpp/health_check_service_interface.h", 
+      "include/grpcpp/health_check_service_interface_impl.h", 
       "include/grpcpp/impl/call.h", 
       "include/grpcpp/impl/channel_argument_option.h", 
       "include/grpcpp/impl/client_unary_call.h",