Emoticons not correctly vertically aligned in wiki content

Discussed with pkuo this morning, I don't think this has been resolved properly since the 5.0 work.

When you zoom in you can see that the emoticon doesn't sit vertically centred in relation to the text, it sits a pixel or two too low (see attached).

As mentioned on https://jira.atlassian.com/browse/CONFDEV-15193, setting vertical-align to text-bottom seems to set the alignment correctly, at least in my browser (Chrome).

I've been using this page as a test: https://pug.jira.com/wiki/pages/viewpage.action?pageId=492535859

I'm on Chrome, we're seeing it in Safari and Firefox also.

Set priority as major as this has been lingering for a while.