`<chrono>`: Add comments for compiler bug workarounds (#4920)

Co-authored-by: Stephan T. Lavavej <stl@nuwen.net>

stl/inc/chrono

@@ -2209,6 +2209,7 @@ namespace chrono {
             auto [_Icu_version, _Zones, _Links] = _Tzdb_generate_time_zones();
             auto [_Leap_sec, _All_ls_positive]  = _Tzdb_generate_leap_seconds(0);
             auto _Version                       = _Icu_version + "." + _STD to_string(_Leap_sec.size());
+            // TRANSITION, VSO-2228186, should call emplace_front with construction arguments
             _Tzdb_list.emplace_front(tzdb{
                 _STD move(_Version), _STD move(_Zones), _STD move(_Links), _STD move(_Leap_sec), _All_ls_positive});
         }
@@ -2266,6 +2267,7 @@ namespace chrono {
                 }
 
                 auto _Version = _Tzdb_update_version(_Tzdb.version, _Leap_sec.size());
+                // TRANSITION, VSO-2228186, should call emplace_front with construction arguments
                 _Tzdb_list.emplace_front(tzdb{
                     _STD move(_Version), _STD move(_Zones), _STD move(_Links), _STD move(_Leap_sec), _All_ls_positive});
             }