[Groff] Invalid HTML on groff website

[Steffen Nurpmeso]

Stumbled over during finding the ultimative underline mail-archive
entry, why did i look at the source?, but indeed [1] at least
embeds a <ul> in a <p>, has a useless </p> and keeps a <small>
open over <p> boundaries.
Just in case noone noticed it yet.
Still looks pretty pretty nonetheless and imho.

  [1] <http://www.gnu.org/software/groff/>

--steffen