Update messages' plural rules from CLDR data

[akx]

Our _GettextCompiler emits suboptimal expressions, and the fix to generate more optimal ones isn't completely trivial, so this uses the ones generated by https://github.com/php-gettext/Languages instead.

Fixes #495
Fixes #711
Fixes #816
Fixes #817
Closes #1289 (duplicate; this one has more thorough coverage)
Closes #768 (duplicate; this one has more thorough coverage)

[codspeed-hq]

Merging this PR will not alter performance

✅ 88 untouched benchmarks

---

_{Comparing prules2 (a70e5df) with master (dd3c275)}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.12%. Comparing base (dd3c275) to head (a70e5df).

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1303   +/-   ##
=======================================
  Coverage   92.12%   92.12%           
=======================================
  Files          27       27           
  Lines        4737     4737           
=======================================
  Hits         4364     4364           
  Misses        373      373           

Flag	Coverage Δ
macos-14-3.10	91.17% <ø> (ø)
macos-14-3.11	91.11% <ø> (ø)
macos-14-3.12	91.32% <ø> (ø)
macos-14-3.13	91.32% <ø> (ø)
macos-14-3.14	91.30% <ø> (ø)
macos-14-3.15	91.30% <ø> (ø)
macos-14-3.8	91.04% <ø> (ø)
macos-14-3.9	91.10% <ø> (ø)
macos-14-pypy3.10	91.17% <ø> (ø)
ubuntu-24.04-3.10	91.19% <ø> (ø)
ubuntu-24.04-3.11	91.13% <ø> (ø)
ubuntu-24.04-3.12	91.34% <ø> (ø)
ubuntu-24.04-3.13	91.34% <ø> (ø)
ubuntu-24.04-3.14	91.32% <ø> (ø)
ubuntu-24.04-3.15	91.32% <ø> (ø)
ubuntu-24.04-3.8	91.06% <ø> (ø)
ubuntu-24.04-3.9	91.12% <ø> (ø)
ubuntu-24.04-pypy3.10	91.19% <ø> (ø)
windows-2022-3.10	91.18% <ø> (ø)
windows-2022-3.11	91.12% <ø> (ø)
windows-2022-3.12	91.33% <ø> (ø)
windows-2022-3.13	91.33% <ø> (ø)
windows-2022-3.14	91.31% <ø> (ø)
windows-2022-3.15	91.31% <ø> (ø)
windows-2022-3.8	91.16% <ø> (ø)
windows-2022-3.9	91.11% <ø> (ø)
windows-2022-pypy3.10	91.18% <ø> (ø)

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