This patch adds the subject icon (smiley, thumbs up, etc.) at the end of the subject on comment notification emails (HTML version only, obviously).
Sometimes the subject icon changes the meaning or alters the mood of a comment. Receiving the comment without the subject icon may be misleading in these cases.
I tested both replies to the post and replies to a comment. Each time, the email showed the subject icon.
(View the aftermath)
It took me waaaay too long to figure out how to do this. If I made a mistake, please let me know.