Add Hong Kong holidays for 2026

[DMZ22]

Adds the 2026 ad-hoc holidays for the Hong Kong calendar, following the pattern of the existing per-year blocks (the latest was 2025).

Dates are from the HK Government's official 2026 general holidays list, cited in a // data from ... comment above the block as was done for 2025:

• Lunar New Year: Feb 17–19 (Tue–Thu)
• The day following Easter Monday: Apr 7 — Ching Ming falls on Sunday Apr 5, so its substitute is Monday Apr 6, which coincides with Easter Monday (already covered by the rule-based section); the government therefore gazetted an additional general holiday on Tue Apr 7. This is the same Easter/Ching Ming overlap as 2015, and the entry uses the same comment wording as the existing 2015 block.
• Buddha's birthday: May 25 (Mon substitute; the day itself falls on Sunday May 24)
• Tuen Ng festival: Jun 19 (Fri)
• Chung Yeung festival: Oct 19 (Mon substitute; the festival falls on Sunday Oct 18)

Omitted, consistent with existing years:

• The day following Good Friday (Sat Apr 4) and the day following Mid-Autumn (Sat Sep 26) fall on Saturdays and are covered by isWeekend — matching how earlier year blocks (e.g. 2019, 2025) omit weekend-falling festival days.
• New Year's Day, Good Friday, Easter Monday, Labour Day, SAR Establishment Day, National Day, Christmas and Boxing Day are covered by the rule-based section above the year blocks.

The Apr 7 closure was additionally cross-checked against HKEX's own calendar, which shows it as a non-trading day.

Sources:

• https://www.gov.hk/en/about/abouthk/holiday/2026.htm
• https://www.hkex.com.hk/News/HKEX-Calendar?sc_lang=en&datefrom=2026-04-07

[boring-cyborg]

Thanks for opening this pull request! It might take a while before we look at it, so don't worry if there seems to be no feedback. We'll get to it.

[CLAassistant]

All committers have signed the CLA.

[coveralls]

coverage: 74.948% (-0.006%) from 74.954% — DMZ22:add-hk-2026-holidays into lballabio:master

[boring-cyborg]

Congratulations on your first merged pull request!