[Localization] Add counts localization for non-English languages

[SadmL]

Problem I have

In Russian and in other slavic languages (and not only them, I guess) we have different word endings (+suffixes sometimes).
As I wrote on Crowdin:

1 post = 1 пост (same applyable for 11, 21, 31 and so on)
2 - 4 post(s) = 2 - 4 пост(а) (12-14, 22-24, 32-34 and so on)
5 - 10 post(s) = 5 - 10 пост(ов) (15-20, 25-30, 35-40 and so on)

I don't like using multiple endings in round squares, it's look meh.
Example - Подпис(ка/ки/ок) (Follow/2-4 Follows/5-10 Follows)

Solution I'd like

Using formulas like this, as far as I understand

Thing is I don't know how to adapt it for other languages if they have different rules for count.
I guess, only if separate this formulas for different languages (if it possible on Crowdin), but it is additional mind load for dev how to manage it properly...

Alternatives considered

No response

Other

No response

[cheeaun]

You'll need to learn the ICU Message Format syntax. Some links here:

• https://lingui.dev/guides/message-format
• https://support.crowdin.com/icu-message-syntax/
• https://cldr.unicode.org/index/cldr-spec/plural-rules

Here's a list of rules for all languages: https://www.unicode.org/cldr/charts/45/supplemental/language_plural_rules.html

e.g. Russian:

[SadmL]

Um, if I understand it correctly, in case of slavic languages it will be
{0, plural, =0 {# "translated word in needed form"} one {# "translated word in needed form"} few {# "translated word in needed form"} other {# "translated word in needed form"}}
for counts
"0" in this case is starting point to count (?)

[cheeaun]

Seems like the starting zero in {0, plural… is the variable, like {count, plural…, but it became "0" due to the library unable to extract a readable variable name out of the code… 😅

I suppose you can ignore the starting "0" for now. I'll look into making them more readable, maybe changing the "0" to "repliesCount" for example, but a bunch of strings will have to be retranslated again.