Merge branch 'bwill/update-auto-resolve-documentation' into 'master'

Document that dismissed vulnerabilities are excluded from vulnerability management policy

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/183578



Merged-by: Brendan Lynch <blynch@gitlab.com>
Approved-by: Brendan Lynch <blynch@gitlab.com>
Reviewed-by: Brendan Lynch <blynch@gitlab.com>
Co-authored-by: Brian Williams <bwilliams@gitlab.com>