Merge branch 'feat/RTE-iteration-autocomplete' into 'master'

add iteration autocomplete to RTE

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/175785



Merged-by: Himanshu Kapoor <info@fleon.org>
Approved-by: Nick Leonard <nleonard@gitlab.com>
Approved-by: Himanshu Kapoor <info@fleon.org>
Reviewed-by: Nick Leonard <nleonard@gitlab.com>
Co-authored-by: Salihu <salihudickson@gmail.com>