Merge branch '438300-doc' into 'master'

Document ai_question_category event

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/142380



Merged-by: Nicolas Dular <ndular@gitlab.com>
Approved-by: Sebastian Rehm <srehm@gitlab.com>
Reviewed-by: Mark Chao <mchao@gitlab.com>
Reviewed-by: Nicolas Dular <ndular@gitlab.com>
Reviewed-by: Sebastian Rehm <srehm@gitlab.com>
Co-authored-by: Mark Chao <mchao@gitlab.com>