docs: drop stale FEATURES-dict references from comments and docstrings

These flags are now flat Django settings, but several comments/docstrings still described
them as FEATURES-dict keys, and each kept a 'settings.FEATURES' reference alive in a
repo-wide grep. Update them to the flat setting they now describe:
- embargo/middleware.py: settings.FEATURES['EMBARGO'] -> settings.EMBARGO
- git_export.py: FEATURE['ENABLE_EXPORT_GIT'] -> ENABLE_EXPORT_GIT setting
- auto_auth.py: settings.FEATURES['AUTOMATIC_AUTH_FOR_TESTING'] -> settings.AUTOMATIC_AUTH_FOR_TESTING
- split_mongo/split.py: reword the historical entrance-exams comment off the dict syntax
- test_auto_auth.py: update the setUp comments to name the flat setting

No code/behavior change; comment/docstring text only.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: feanil

cms/djangoapps/contentstore/management/commands/git_export.py

@@ -10,7 +10,7 @@
 any have taken place.
 
 This functionality is also available as an export view in studio if the giturl
-attribute is set and the FEATURE['ENABLE_EXPORT_GIT'] is set.
+attribute is set and the ENABLE_EXPORT_GIT setting is enabled.
 """
 
 

openedx/core/djangoapps/embargo/middleware.py

@@ -16,7 +16,7 @@
 
 Usage:
 
-1) Enable embargo by setting `settings.FEATURES['EMBARGO']` to True.
+1) Enable embargo by setting `settings.EMBARGO` to True.
 
 2) In Django admin, create a new `IPFilter` model to block or whitelist
     an IP address from accessing the site.

openedx/core/djangoapps/user_authn/views/auto_auth.py

@@ -43,7 +43,7 @@ def auto_auth(request):  # pylint: disable=too-many-statements
     Create or configure a user account, then log in as that user.
 
     Enabled only when
-    settings.FEATURES['AUTOMATIC_AUTH_FOR_TESTING'] is true.
+    settings.AUTOMATIC_AUTH_FOR_TESTING is true.
 
     Accepts the following querystring parameters:
     * `username`, `email`, and `password` for the user account

openedx/core/djangoapps/user_authn/views/tests/test_auto_auth.py

@@ -47,7 +47,7 @@ class AutoAuthEnabledTestCase(AutoAuthTestCase, ModuleStoreTestCase):
 
     @override_settings(AUTOMATIC_AUTH_FOR_TESTING=True)
     def setUp(self):
-        # Patching the settings.FEATURES['AUTOMATIC_AUTH_FOR_TESTING']
+        # Patching the AUTOMATIC_AUTH_FOR_TESTING setting
         # value affects the contents of urls.py,
         # so we need to call super.setUp() which reloads urls.py (because
         # of the UrlResetMixin)
@@ -305,7 +305,7 @@ class AutoAuthDisabledTestCase(AutoAuthTestCase):
 
     @override_settings(AUTOMATIC_AUTH_FOR_TESTING=False)
     def setUp(self):
-        # Patching the settings.FEATURES['AUTOMATIC_AUTH_FOR_TESTING']
+        # Patching the AUTOMATIC_AUTH_FOR_TESTING setting
         # value affects the contents of urls.py,
         # so we need to call super.setUp() which reloads urls.py (because
         # of the UrlResetMixin)
@@ -329,7 +329,7 @@ class AutoAuthRestrictedTestCase(AutoAuthTestCase):
 
     @override_settings(AUTOMATIC_AUTH_FOR_TESTING=True)
     def setUp(self):
-        # Patching the settings.FEATURES['AUTOMATIC_AUTH_FOR_TESTING']
+        # Patching the AUTOMATIC_AUTH_FOR_TESTING setting
         # value affects the contents of urls.py,
         # so we need to call super.setUp() which reloads urls.py (because
         # of the UrlResetMixin)

xmodule/modulestore/split_mongo/split.py

@@ -1720,7 +1720,7 @@ def create_child(self, user_id, parent_usage_key, block_type, block_id=None, fie
 
             parent = new_structure['blocks'][block_id]
 
-            # Originally added to support entrance exams (settings.FEATURES.get('ENTRANCE_EXAMS'))
+            # Originally added to support entrance exams (the ENTRANCE_EXAMS feature)
             if kwargs.get('position') is None:
                 parent.fields.setdefault('children', []).append(BlockKey.from_usage_key(xblock.location))
             else: