gh issue comment {<number> | <url>} [flags]
Add a comment to a GitHub issue.
Without the body text supplied through flags, the command will interactively prompt for the comment text.
-b,
--body <text>-F,
--body-file <file>--create-if-none--delete-last--edit-last-e,
--editor-w,
--web--yes-R,
--repo <[HOST/]OWNER/REPO>$ gh issue comment 12 --body "Hi from GitHub CLI"