add some std.date types

Author: clickingbuttons

lib/std/date.zig

@@ -5,6 +5,9 @@ pub const epoch = @import("./date/epoch.zig");
 ///
 /// Supports dates between years -32_768 and 32_768.
 pub const Date = gregorian.Date(i16, epoch.posix);
+pub const Month = Date.Month;
+pub const Day = Date.Day;
+pub const Weekday = Date.Weekday;
 
 test {
     _ = gregorian;