Re: [groff] 27/33: eqn(1): Fix content and style nits.

[Dave Kemper]

>     * Drop internal cross reference to material about "translation limits"
>       that doesn't seem to be present (and never has been according to "git
>       log").

Commit d239103a7, an extensive eqn overhaul in which Eric Raymond
added MathML output, added this cross reference pointing to the "Bugs"
section, as well as two items in that section (each beginning with "In
MathML mode, ...").  So I think it's fair to say the reference
referred to those two items, even if its wording doesn't make that
clear.  (It doesn't to me either.)  The two "In MathML mode" items in
"Bugs" survive to this day, so this wasn't a dangling reference,
merely a murky one.

Whether that justifies restoring it (with clarified wording) is a
different question.  The cross reference was in the "MathML mode
limitations" section, pointing to further information about MathML
limitations, but arguably the two items under "Bugs" could just as
easily be classified as limitations, so simply moving them might be
more straightforward.  (Since they're limitations that might one day
be removed, rather than ones inherent in the design differences
between eqn and MathML, I can see why Eric filed them in a separate
place, but I'm not convinced that raises them to the level of bugs.)