Comment 3 for bug 758667

Does the Kindle renderer even respect font size inside sup/sub tags? You
should be able to easily check this by hardcoding a font size tag inside <sup>
in mobiml.py.

If you want <sup>x<sub>y</p> could mean that y should be a subscript of x and
the author forgot to close the tags. I'd rather not play these kinds
of guessing games.