Basque date declination

[uloidi]

Hello,

The Basque date declination grammar requires some logic but we can't introduce due to the software design.

Here is a clear example of the problem:

Current Django Output: 2025ko urriaren 11a
Correct Grammatical Form: 2025eko urriaren 11

There are two errors here based on conditional rules:

Year Suffix: It should be 2025eko. The suffix changes based on the last sound of the year number. Years ending in a consonant sound (like 2025, bost) must use -eko, while the current output -ko is for years ending in a vowel (like 2024, lau).
Day Article: It should be 11. The -a article should not be added to numbers that already end in the vowel ‘a’. The number 11 in Basque is hamaika, so adding another -a (hamaika-a) is grammatically wrong.

My proposal is to change the Basque (eu) date template with "(e)ko" instead of "ko" in the year suffix and "(a)" instead of "a" in the day suffix

[uloidi]

​https://github.com/django/django/pull/19988