update tg_context_patch for python 3.12

conftest.py

@@ -17,8 +17,6 @@
 import pytest
 
 # should get rid of this once this issue is fixed https://github.com/TurboGears/tg2/issues/136
-
-
 @pytest.fixture(autouse=True, scope='session')
 def tg_context_patch():
     from tg import (
@@ -31,11 +29,12 @@ def tg_context_patch():
         url,
         config,
     )
-    r.__dict__['_is_coroutine'] = False
-    c.__dict__['_is_coroutine'] = False
-    g.__dict__['_is_coroutine'] = False
-    cache.__dict__['_is_coroutine'] = False
-    response.__dict__['_is_coroutine'] = False
-    translator.__dict__['_is_coroutine'] = False
-    url.__dict__['_is_coroutine'] = False
-    config.__dict__['_is_coroutine'] = False
+    for marker in ('_is_coroutine', '_is_coroutine_marker'):
+        r.__dict__[marker] = False
+        c.__dict__[marker] = False
+        g.__dict__[marker] = False
+        cache.__dict__[marker] = False
+        response.__dict__[marker] = False
+        translator.__dict__[marker] = False
+        url.__dict__[marker] = False
+        config.__dict__[marker] = False