https://git.savannah.gnu.org/cgit/emacs/org-mode.git/tree/lisp/ol.el#n1856
(insert "Insert a link.
Use TAB to complete link prefixes, then RET for type-specific completion
support\n")
This causes a stretch in the message buffer, which sometimes is being a
little bit annoying, I'm advising org-link-insert personally because of
it.
Maybe merging it into one line:
(insert "Insert a link. Use TAB to complete link prefixes, then RET for
type-specific completion support\n")
Will make it better.
--
Regards,
Salih