Refs #25466 -- Removed aliases for LoaderOrigin and StringOrigin.

Per deprecation timeline.

django/template/__init__.py

@@ -58,8 +58,7 @@ from .exceptions import TemplateDoesNotExist, TemplateSyntaxError       # NOQA i
 
 # Template parts
 from .base import (                                                     # NOQA isort:skip
-    Context, Node, NodeList, Origin, RequestContext, StringOrigin, Template,
-    Variable,
+    Context, Node, NodeList, Origin, RequestContext, Template, Variable,
 )
 
 # Library management

django/template/base.py

@@ -60,9 +60,7 @@ from django.template.context import (  # NOQA: imported for backwards compatibil
     BaseContext, Context, ContextPopException, RequestContext,
 )
 from django.utils import six
-from django.utils.deprecation import (
-    DeprecationInstanceCheck, RemovedInDjango20Warning,
-)
+from django.utils.deprecation import RemovedInDjango20Warning
 from django.utils.encoding import (
     force_str, force_text, python_2_unicode_compatible,
 )
@@ -163,11 +161,6 @@ class Origin(object):
             )
 
 
-class StringOrigin(six.with_metaclass(DeprecationInstanceCheck, Origin)):
-    alternative = 'django.template.Origin'
-    deprecation_warning = RemovedInDjango20Warning
-
-
 class Template(object):
     def __init__(self, template_string, origin=None, name=None, engine=None):
         try:

django/template/loader.py

 from django.utils import six
-from django.utils.deprecation import (
-    DeprecationInstanceCheck, RemovedInDjango20Warning,
-)
 
 from . import engines
-from .base import Origin
 from .exceptions import TemplateDoesNotExist
 
 
@@ -70,8 +66,3 @@ def render_to_string(template_name, context=None, request=None, using=None):
 
 def _engine_list(using=None):
     return engines.all() if using is None else [engines[using]]
-
-
-class LoaderOrigin(six.with_metaclass(DeprecationInstanceCheck, Origin)):
-    alternative = 'django.template.Origin'
-    deprecation_warning = RemovedInDjango20Warning

docs/releases/2.0.txt

@@ -315,3 +315,7 @@ these features.
 
 * The ``enclosure`` keyword argument to ``SyndicationFeed.add_item()`` is
   removed.
+
+* The ``django.template.loader.LoaderOrigin`` and
+  ``django.template.base.StringOrigin`` aliases for
+  ``django.template.base.Origin`` are removed.