For a quick workaround, add a couple line to [[MediaWiki:Enotif_body]] like:

To change your email notification settings, visit
{{fullurl:{{#special:Preferences}}}}

Unfortunately the whole email body is a single message, so updating it in core will require updating all localizations, *and* any customized sites might need to update theirs.

Went ahead and added this for the English messages on trunk in r88294.

I *think* LocalisationUpdate should pick it up automatically after a bit where the message hasn't already been customized; any localizations already existing for this message will need to be updated in TranslateWiki.

Roan reminded me that LU won't pick up a change in English localizations, so he's merging to deployment to get it out.