Reduce the number of items in the feed to 30

Hopefully a good compromise when you discover it

site.py

@@ -32,6 +32,7 @@ LOCAL_DOMAIN = "http://larlet.test:3579"
 NORMALIZED_STRFTIME = "%Y-%m-%dT12:00:00+01:00"
 TODAY = datetime.today() + timedelta(hours=6)
 PUBLICATION_BUFFER = TODAY - timedelta(days=7)
+NB_ITEMS_IN_FEED = 30
 
 
 class MarkParser(mistune.InlineParser):
@@ -297,8 +298,9 @@ def home():
 def feed():
     """Generate a feed from last published items."""
     template = environment.get_template("feed.xml")
+    page_list = Page.all(source=DAVID / "2021" / "sources", with_h2_anchors=False)
     content = template.render(
-        page_list=Page.all(source=DAVID / "2021" / "sources", with_h2_anchors=False),
+        page_list=page_list[:NB_ITEMS_IN_FEED],
         current_dt=TODAY.strftime(NORMALIZED_STRFTIME),
         BASE_URL=f"{DOMAIN}/david/",
     )