bug#53702: 27.1; diary does not display some entries in european style

[Francesco Potortì]

Diary entries are not parsed by M-x diary if:
- calendar-date-style is set to european (rather than american)
AND
- the date is written as "3 Feb" (rather than 3/2)
AND
- the time is written as "18.00" (rather than 18:00)

At least, this is what I have found by trial and error.  I looked at the code 
in appt.el and diary-lib.el but was not able to find the culprit...

To reproduce:

$ emacs -Q -nw --load=appt-bug.el

You will see that only two european entries are shown (t1 and t2).

Then exit Emacs, comment out the second line in appt-bug-el and rerun Emacs as 
above: you will see four american entries (t1, t2, t3, t4).


================ appt-bug.el
(setq diary-file "~/appt-bug-diary"
      calendar-date-style 'european
      )
(load-library "diary-lib")
(diary-list-entries (list 2 3 (decoded-time-year (decode-time))) 1)


================ appt-bug-diary
        -*-diary-*-

3 Feb   18:00 t1 works (european)

3/2     18.00 t2 works (european)

3 Feb   18.00 t3 does not work (european)

3 Feb
        18.00 t4 does not work (european)

Feb 3   18:00 t1 works (american)

2/3     18.00 t2 works (american)

Feb 3   18.00 t3 works (american)

Feb 3
        18.00 t4 works (american)