Add code examples to the User class

The methods `User.contributor_subreddits` and `User.subreddits` need to
use either an explicit limit or a limit of None in order to retrieve more than
100 subreddits.

(cherry picked from commit 1bceed35e830837dd16ae50315fc2671d4e4ac81)

asyncpraw/models/user.py

@@ -65,11 +65,18 @@ def contributor_subreddits(
     ) -> AsyncIterator["asyncpraw.models.Subreddit"]:
         """Return a :class:`.ListingGenerator` of contributor subreddits.
 
-        These are subreddits that the user is a contributor of.
+        These are subreddits in which the user is an approved user.
 
         Additional keyword arguments are passed in the initialization of
         :class:`.ListingGenerator`.
 
+        To print a list of the subreddits that you are an approved user in, try:
+
+        .. code-block:: python
+
+            async for subreddit in reddit.user.contributor_subreddits(limit=None):
+                print(str(subreddit))
+
         """
         return ListingGenerator(
             self._reddit, API_PATH["my_contributor"], **generator_kwargs
@@ -193,6 +200,13 @@ def subreddits(
         Additional keyword arguments are passed in the initialization of
         :class:`.ListingGenerator`.
 
+        To print a list of the subreddits that you are subscribed to, try:
+
+        .. code-block:: python
+
+            async for subreddit in reddit.user.subreddits(limit=None):
+                print(str(subreddit))
+
         """
         return ListingGenerator(
             self._reddit, API_PATH["my_subreddits"], **generator_kwargs