docs fail to build with doxygen 1.9.4

With doxygen 1.9.4, first we have an error about the CLASS_GRAPH option being set when the deprecated CLASS_DIAGRAMS is set.

Then we have:

CMake Error at src/api/docs/CMake_rundoxygen.cmake:154 (message):
  *** /usr/bin/doxygen failed: ***

  
  build_x64_dbg_tests/include/dr_config.h:683:
  warning: The following parameter of dr_register_client(const char
  *process_name, process_id_t pid, bool global, dr_platform_t dr_platform,
  client_id_t client_id, size_t client_pri, const char *client_path, const
  char *client_options) is not documented:

    parameter 'client_options'

  
  build_x64_dbg_tests/include/dr_events.h:133:
  warning: found documented return type for dr_register_bb_event that does
  not return anything

  
  build_x64_dbg_tests/include/dr_events.h:367:
  warning: found documented return type for dr_register_trace_event that does
  not return anything

  src/api/docs/deployment.dox:751:
  warning: Invalid list item found

  src/api/docs/deployment.dox:751:
  warning: Invalid list item found

I understand the two return type ones and I can fix those. I do not understand the others yet.