Merge branch '419106-paste-from-markdown-docs' into 'master'

Allow pasting a markdown block

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/126993



Merged-by: Enrique Alcántara <ealcantara@gitlab.com>
Approved-by: Enrique Alcántara <ealcantara@gitlab.com>
Co-authored-by: Himanshu Kapoor <hkapoor@gitlab.com>