Merge pull request #1492 from LukashonakV/master

#1315. Add option to display week number on calendar

include/modules/clock.hpp

@@ -36,6 +36,8 @@ class Clock : public ALabel {
   auto weekdays_header(const date::weekday& first_dow, std::ostream& os) -> void;
   auto first_day_of_week() -> date::weekday;
   const date::time_zone* current_timezone();
+  auto print_iso_weeknum(std::ostream& os,
+                         int weeknum) -> void;
   bool is_timezone_fixed();
   auto timezones_text(std::chrono::system_clock::time_point* now) -> std::string;
 };