my_locale_month_names_ka_GE[] has definitions for 11 months only.
August was missing in a mistake.
Fix:
- Adding a definition for August
- Adding tests for all abbreviated and full month and weekday names
MDEV-28227 added the error messages in simplified characters.
Lets use these for those running a zh_CN profile.
From Haidong Ji in the MDEV, Taiwan/Hong Kong (zh_TW/zh_HK)
would expect traditional characters so this is left for when
we have these.
