Fix spelling in URLs

CHANGELOG.rst

@@ -26,6 +26,7 @@ Fixed
 * Optimize exam model and add reference to exams at extra lessons.
 * Lessons weren't shown as cancelled on teacher or room timetables
   if events had replaced them.
+* The URLs containing the term "substitution" were missspelled.
 
 `2.3`_ - 2022-03-21
 -------------------

aleksis/apps/chronos/urls.py

@@ -34,12 +34,12 @@ urlpatterns = [
         name="lessons_day_by_date",
     ),
     path(
-        "lessons/<int:id_>/<int:week>/substition/",
+        "lessons/<int:id_>/<int:week>/substitution/",
         views.edit_substitution,
         name="edit_substitution",
     ),
     path(
-        "lessons/<int:id_>/<int:week>/substition/delete/",
+        "lessons/<int:id_>/<int:week>/substitution/delete/",
         views.delete_substitution,
         name="delete_substitution",
     ),