bug#61460: 30.0.50; Calendar shows eclipse for quarter moon

[Ulrich Mueller]

>>>>> On Sat, 18 Feb 2023, Michael Heerdegen wrote:

> Thank you for your work.  This one was very interesting!

Yeah, this one was fun. :)

I was also tempted to add a defcustom for the eclipse names, so we could
have "Sonnenfinsternis", etc. Then again, the additional word "possible"
in these messages made me feel that we're in l10n/gettext territory, and
presumably it should be solved in a more general context (there was a
discussion on emacs-devel in 2021).