Merge branch 'ld-docs-github-negated-helper' into 'master'

Document GraphQL negated helper

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/141730



Merged-by: Pavel Shutsin <pshutsin@gitlab.com>
Approved-by: Pavel Shutsin <pshutsin@gitlab.com>
Co-authored-by: Luke Duncalfe <lduncalfe@eml.cc>