`<chrono>`: `std::chrono::locate_zone` should use binary search

[cpplearner]

[time.zone.db.tzdb]/1:

Each vector in a tzdb object is sorted to enable fast lookup.

The time zone names are sorted in the tzdb produced by MSVC's STL¹, but locate_zone performs a linear search. It could be changed to a binary search, which would be faster.

STL/stl/inc/chrono

Lines 2106 to 2110 in 41ec195

	template <class _Ty>
	_NODISCARD const _Ty* _Locate_zone_impl(const vector<_Ty>& _Vec, string_view _Name) {
	const auto _Result = _STD find_if(_Vec.begin(), _Vec.end(), [&](auto& _Tz) { return _Tz.name() == _Name; });
	return _Result == _Vec.end() ? nullptr : &*_Result;
	}

This is slightly more advanced than a "good first issue", requiring the contributor to understand how to perform binary search using std::lower_bound (not std::binary_search!).

Footnotes

1. The data are obtained from ICU, and eventually from the zoneinfo64 resource. zoneinfo64 is generated by tz2icu, which sorts the names by using a std::map. ↩