User:GTrang/To do/2022

* ✅ Add 2021 to the "Historical years" cateory and update its description.
 * ✅ Remove 2022 from the "Future years" category and update its description.
 * Update the bold link in the "Years in century" template to refer to 2022 instead of 2021.
 * Update holiday pages and the corresponding monthly calendar templates to refer to 2022 instead of 2021.