Replace 'trivial' with 'proof of concept'

(cherry picked from commit bb0e00025f4cf10be64469d8998cc6ae1d81ca8c)

asyncpraw/util/token_manager.py

@@ -3,8 +3,8 @@
 There should be a 1-to-1 mapping between an instance of a subclass of
 :class:`.BaseTokenManager` and a :class:`.Reddit` instance.
 
-A few trivial token manager classes are provided here, but it is expected that Async
-PRAW users will create their own token manager classes suitable for their needs.
+A few proof of concept token manager classes are provided here, but it is expected that
+Async PRAW users will create their own token manager classes suitable for their needs.
 
 See :ref:`using_refresh_tokens` for examples on how to leverage these classes.
 
@@ -62,7 +62,7 @@ def pre_refresh_callback(self, authorizer):
 
 
 class FileTokenManager(BaseTokenManager):
-    """Provides a trivial single-file based token manager.
+    """Provides a single-file based token manager.
 
     It is expected that the file with the initial ``refresh_token`` is created prior to
     use.