Fixed #36138 -- Changed ADMINS and MANAGERS settings to lists of strings.

Previously, the ADMINS and MANAGERS settings were lists of (name, address)
tuples (where the name had been unused). Deprecated use of tuples.

Updated settings value sanity checks, and changed from ValueError to
ImproperlyConfigured.

docs/internals/contributing/writing-documentation.txt

@@ -606,15 +606,7 @@ example:
 
     Default: ``[]`` (Empty list)
 
-    A list of all the people who get code error notifications. When
-    ``DEBUG=False`` and a view raises an exception, Django will email these people
-    with the full exception information. Each member of the list should be a tuple
-    of (Full name, email address). Example::
-
-        [("John", "john@example.com"), ("Mary", "mary@example.com")]
-
-    Note that Django will email *all* of these people whenever an error happens.
-    See :doc:`/howto/error-reporting` for more information.
+    A list of all the people who get code error notifications...
 
   This marks up the following header as the "canonical" target for the
   setting ``ADMINS``. This means any time I talk about ``ADMINS``,

docs/internals/deprecation.txt

@@ -28,6 +28,9 @@ details on these changes.
 
 * The ``URLIZE_ASSUME_HTTPS`` transitional setting will be removed.
 
+* Support for setting the ``ADMINS`` or ``MANAGERS`` settings to a list of
+  (name, address) tuples will be removed.
+
 .. _deprecation-removed-in-6.1:
 
 6.1