[FIX] sap.ui.core.format.DateFormat: escape calendar week pattern

[martindglaser]

Summary

When parsing the wide/narrow week-in-year field, DateFormat turns the localized calendar-week text from LocaleData#getCalendarWeek into a RegExp without escaping its literal part:

sPart = oFormat.oLocaleData.getCalendarWeek(...);   // e.g. hu narrow: "{0}. NH"
sPart = sPart.replace("{0}", "([0-9]+)");
var rWeekNumber = new RegExp(sPart);                 // "([0-9]+). NH"

[kgogov]

Hello @martindglaser,

Thank you for creating this PR — much appreciated! 🙌

I've created internal incident DINC0976856 to track this. Colleagues responsible for this module will look it up soon, and I'll keep the status updated here.

Regards,
Konstantin

[1110101]

Hi, thanks for your contribution! Im part of the team which is responsible for DateFormat and took a quick look before the weekend. Could you please add a new or extend an existing unit test for this?

[martindglaser]

Thanks @1110101! I've extended the existing "format and parse weekInYear pattern" test in DateFormat.qunit.js to cover the Hungarian narrow calendar-week pattern ("{0}. NH"): it formats the narrow week, parses it back, and asserts that a corrupted separator (". NH" → "X NH") is now rejected — this case parses successfully before the fix (the . acts as a wildcard) and returns null after it. Amended into the same commit. Let me know if you'd prefer it split into a dedicated test or extended to the wide pattern as well.