Add ’ (Apostrophe) character to link_validate_url

Issue Summary

I had a valid internal URL that was being marked as invalid.

The internal path is: the-experience/blog/roger-federer-is-moet-chandon’s-new-brand-ambassador.

After adding ’ (apostrophe) character to $LINK_ICHARS_DOMAIN, the problem went away.

I know the $LINK_ICHARS_DOMAIN isn't the right place to place this character, but I'm not too experienced with regex expressions. Could you add this character to the validation function?

Thanks a lot.