Replace 'Embed' hint on Pholio

Summary: Replaces Embed hint with where the heck you are hint.

Test Plan: Tested current and previous mock images.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T5384

Differential Revision: https://secure.phabricator.com/D9658