[lmi] [PATCH] Improve cohesion of unbreakable paragraphs

[Vadim Zeitlin]

 Hello,

 Before submitting a more extensive and important header-related patch, I'd
like to submit https://github.com/vadz/lmi/pull/94 which is less critical,
but also much simpler. This patch doesn't change any observable behaviour
right now, but it ensures that if we ever use any tags inside the text of
the paragraphs supposed to be unbreakable (i.e. remain entirely on a single
physical page), they will remain so, instead of splitting on the location
of these tags.

 E.g. currently inserting a line break (<br>) inside the contents of the
"Policy Year" paragraph in the "Explanatory Notes" page can split it in two
parts. With this patch, it remains on the same (next) page.

 This patch is not very urgent as we don't have any tags whatsoever inside
the unbreakable paragraphs text currently, but I'd like it to be applied
nevertheless because the problem it solves is not completely trivial and it
would take anybody (including me, who will have forgotten everything about
it by then) a lot of time to fix it again if it does arise in the future.
Also, this patch is quite simple, even if it's also undoubtedly somewhat
ugly -- but to the best of my knowledge, there is no other way to convince
wxHTML to do what we want.

 Thanks in advance,
VZ