Remove non-working note box markup within a table

From
https://web.archive.org/web/20211112014222/https://docs.freebsd.org/en/books/handbook/zfs/#zfs-term-quota
and from
https://web.archive.org/web/20211120235121/https://docs.freebsd.org/en/books/handbook/zfs/#zfs-term-quota
it seems that note box markup (below) ceased working, within a table,
some time between 12th and 20th November 2021.

[NOTE]

…

https://openzfs.github.io/openzfs-docs/man/7/zfsprops.7.html#quota
looks fine without using a note box, so let's not attempt to remake
the box in the documentation portal.