Ignore errors fetching robots

Man everybody has trouble with this, don't let a bad server bring you
down here.

cry/feed.py

@@ -371,19 +371,45 @@ class Guardian:
 
     async def crawl_delay(self, url: str) -> int | None:
         """Returns the number of seconds we should wait before fetching again."""
-        parser = await self.get_robots_parser(url)
-        result = parser.crawl_delay(USER_AGENT)
-        if isinstance(result, str):
-            try:
-                return int(result)
-            except ValueError:
-                return None
+        try:
+            parser = await self.get_robots_parser(url)
+            result = parser.crawl_delay(USER_AGENT)
+            if isinstance(result, str):
+                try:
+                    return int(result)
+                except ValueError:
+                    return None
+        except Exception as e:
+            LOG.error(f"Error fetching crawl delay for {url}: {e}")
+            return None
 
 
 GUARDIAN = Guardian()
 
 
-async def fetch_feed(meta: FeedMeta) -> typing.Tuple[str | Feed | None, FeedMeta]:
+async def fetch_feed(meta: FeedMeta) -> typing.Tuple[None | Feed | str, FeedMeta]:
+    """Fetch a feed from the internet. `meta` is a FeedMeta that has all the
+    details about what happened the last time we went to do a fetch, caching
+    information and whatnot.
+
+    The return value is a little funky. It returns a 2-tuple, where the first
+    element is one of:
+
+    - None, if we could not fetch anything
+    - A Feed, if we fetched something and it seemed to be a feed
+    - A string, if we fetched something but it was not a feed
+
+    The second element is a FeedMeta that describes the URL. It might be the
+    same as the FeedMeta that was provided, but it might not be:
+
+    - The etag might have been updated if the server sent us an etag
+    - The modified value might have been updated if the server sent us a
+      new value
+    - The URL might have been updated if we followed a permanent redirect
+
+    Just to be safe, callers should use the new FeedMeta in place of the
+    argument for everything after calling this function.
+    """
     if not meta.should_fetch(time.time()):
         return (None, meta)