Fixed #25838 -- Added "python" as an interface to the shell command.

Deprecates the "--plain" option.

docs/internals/deprecation.txt

@@ -126,6 +126,8 @@ details on these changes.
 
 * ``django.utils.functional.allow_lazy()`` will be removed.
 
+* The ``shell --plain`` option will be removed.
+
 .. _deprecation-removed-in-1.10:
 
 1.10

docs/ref/django-admin.txt

@@ -933,9 +933,15 @@ Starts the Python interactive interpreter.
 
 Django will use IPython_ or bpython_ if either is installed. If you have a
 rich shell installed but want to force use of the "plain" Python interpreter,
-use the ``--plain`` option, like so::
+use the ``-i python`` or ``--interface python`` option, like so::
 
-    django-admin shell --plain
+    django-admin shell -i python
+    django-admin shell --interface python
+
+.. deprecated:: 1.10
+
+   In older versions, use the ``--plain`` option. This is deprecated and will
+   be removed in Django 2.0.
 
 If you would like to specify either IPython or bpython as your interpreter if
 you have both installed you can specify an alternative interpreter interface
@@ -957,12 +963,12 @@ bpython::
 .. _bpython: http://bpython-interpreter.org/
 
 When the "plain" Python interactive interpreter starts (be it because
-``--plain`` was specified or because no other interactive interface is
-available) it reads the script pointed to by the :envvar:`PYTHONSTARTUP`
+``--interface python`` was specified or because no other interactive interface
+is available) it reads the script pointed to by the :envvar:`PYTHONSTARTUP`
 environment variable and the ``~/.pythonrc.py`` script. If you don't wish this
 behavior you can use the ``--no-startup`` option. e.g.::
 
-    django-admin shell --plain --no-startup
+    django-admin shell --interface python --no-startup
 
 showmigrations [<app_label> [<app_label>]]
 ------------------------------------------

docs/releases/1.10.txt

@@ -212,6 +212,9 @@ Management Commands
 * :djadmin:`makemigrations` now displays the path to the migration files that
   it generates.
 
+* The :djadmin:`shell` ``--interface`` option now accepts ``python`` to force
+  use of the "plain" Python interpreter.
+
 Migrations
 ^^^^^^^^^^
 
@@ -432,6 +435,9 @@ Miscellaneous
   :func:`~django.utils.functional.keep_lazy` function which can be used with a
   more natural decorator syntax.
 
+* The ``shell --plain`` option is deprecated in favor of ``-i python`` or
+  ``--interface python``.
+
 .. _removed-features-1.10:
 
 Features removed in 1.10