to quote a very similar question i answered on another site
this is just me but personally i feel that unless the answer is a Community Wiki edits to answers should be limited to formatting, grammar/spelling correction and/or clarification and the only time time i feel to add new stuff to an answer is when you're quoting relevant parts from exiting links or posting something supportive to the existing information presented in the answer (ie. adding a manga page or episode screenshots).
if the rejected edit was incorrect and Ero Sɘnnin did want the information in the answer they can override the rejection being the post owner.
now i would disagree that it should be edited in there because to me it would be superfluous and infact there is a suggested edit reject reason for this
no improvement whatsoever
This edit does not make the post even a little bit easier to read, easier to find, more accurate or more accessible. Changes are either completely superfluous or actively harm readability.
now i agree with Napoleon Wilson ♦'s comment in which it would be better to either flesh out the answer more or post the link as a comment on the original answer