Tasks: split T40 into i18n and a11y

tasks/ch31-43.md

@@ -271,12 +271,15 @@
 - [x] VibrancyBackground / Acrylic → `shell::Vibrancy` in a window opened `WindowBackgroundAppearance::Blurred`
 - [ ] Mica — blocked: gpui 0.2.2's one blur, `Blurred`, is acrylic on Windows
 
-## T40 i18n & a11y — `src/i18n`
+## T40a i18n — `src/i18n`
 
 - [ ] I18nProvider
 - [ ] Trans / LocalizedText
 - [ ] LocaleNumber / LocaleDate
 - [ ] RTL layout — prove: mirrored stacks
+
+## T40b a11y — `src/i18n`
+
 - [ ] LiveRegion / Announcer — blocked: gpui 0.2.2 has no accessibility tree
 - [ ] SkipLink
 - [ ] AccessibleIcon — blocked: no accessibility tree