Fixed #29703 -- Deprecated QuerySetPaginator alias.

Unused since 4406d283e1.

django/core/paginator.py

@@ -3,6 +3,7 @@ import inspect
 import warnings
 from math import ceil
 
+from django.utils.deprecation import RemovedInDjango31Warning
 from django.utils.functional import cached_property
 from django.utils.inspect import method_has_no_args
 from django.utils.translation import gettext_lazy as _
@@ -125,7 +126,14 @@ class Paginator:
             )
 
 
-QuerySetPaginator = Paginator   # For backwards-compatibility.
+class QuerySetPaginator(Paginator):
+
+    def __init__(self, *args, **kwargs):
+        warnings.warn(
+            'The QuerySetPaginator alias of Paginator is deprecated.',
+            RemovedInDjango31Warning, stacklevel=2,
+        )
+        super().__init__(*args, **kwargs)
 
 
 class Page(collections.abc.Sequence):