Fix docs for muted

(cherry picked from commit praw-dev/praw@89c0402)

asyncpraw/models/reddit/subreddit.py

@@ -727,7 +727,7 @@ def muted(self) -> "asyncpraw.models.reddit.subreddit.SubredditRelationship":
 
             subreddit = await reddit.subreddit("test")
             async for mute in subreddit.muted():
-                print("{mute}: {mute.note}")
+                print("{mute}: {mute.date}")
 
         """
         return SubredditRelationship(self, "muted")