Add Christmas day

Closes: #4

agenda/__init__.py

@@ -183,6 +183,11 @@ def next_economist(input_date: date) -> date:
     return next_thursday_date
 
 
+def xmas_day(input_date: date) -> date:
+    """Christmas day."""
+    return date(input_date.year, 12, 25)
+
+
 def uk_financial_year_end(input_date: date) -> date:
     """Next date of the end of the UK financial year, April 5th."""
     # Determine the year of the input date
@@ -279,6 +284,7 @@ def get_data() -> dict[str, str | object]:
         "fathers_day": next_uk_fathers_day(today),
         "uk_financial_year_end": uk_financial_year_end(today),
         "xmas_last_posting_dates": xmas_last_posting_dates,
+        "xmas_day": xmas_day(today),
     }
 
     return reply

templates/index.html

@@ -66,6 +66,11 @@
       {{days(xmas_last_posting_dates["first"])}}
       {{xmas_last_posting_dates["first"].strftime("%a, %d %b %Y")}}</li>
 
+    <li>Christmas day:
+      {{days(xmas_day)}}
+      {{xmas_day.strftime("%a, %d %b %Y")}}</li>
+
+
     </ul>
 
   <h3>Stock markets</h3>