Add support for the “small” HTML tag

I would like if the plugin add support to the <small> HTML tag, an inline element which by default puts the text in a relative smaller size and is used to side disclosures. I use it a lot on wiki-like articles where I have to add a parenthetical note at the side of an item on a list. Sort of like:

Radiohead Setlist for 2017/02/29:

1. A Hard Day’s Night
2. Only You
3. —El Cóndor Pasa <small>(with Joan Baez)</small>
4. —Come on Eileen