Fix `ambiguous_local_time`'s message is slightly incorrect (#3650)

stl/inc/chrono

@@ -6011,7 +6011,7 @@ namespace chrono {
     template <class _Duration>
     _NODISCARD string ambiguous_local_time::_Make_string(const local_time<_Duration>& _Tp, const local_info& _Info) {
         ostringstream _Os;
-        _Os << _Tp << " is ambiguous. It could be\n"
+        _Os << _Tp << " is ambiguous.  It could be\n"
             << _Tp << ' ' << _Info.first.abbrev << " == " << _Tp - _Info.first.offset << " UTC or\n"
             << _Tp << ' ' << _Info.second.abbrev << " == " << _Tp - _Info.second.offset << " UTC";
         return _STD move(_Os).str();

tests/std/tests/P0355R7_calendars_and_time_zones_formatting/test.cpp

@@ -798,11 +798,11 @@ void test_exception_classes() {
         }
 
         assert(s
-                   == "2016-11-06 01:30:00 is ambiguous. It could be\n"
+                   == "2016-11-06 01:30:00 is ambiguous.  It could be\n"
                       "2016-11-06 01:30:00 EDT == 2016-11-06 05:30:00 UTC or\n"
                       "2016-11-06 01:30:00 EST == 2016-11-06 06:30:00 UTC"
                || s
-                      == "2016-11-06 01:30:00 is ambiguous. It could be\n"
+                      == "2016-11-06 01:30:00 is ambiguous.  It could be\n"
                          "2016-11-06 01:30:00 GMT-4 == 2016-11-06 05:30:00 UTC or\n"
                          "2016-11-06 01:30:00 GMT-5 == 2016-11-06 06:30:00 UTC");
     }