try supporting old autodoc_attrgettrs attribute as well as new autodoc_attrgetters attribute

Author: kiwifb

src/sage_docbuild/ext/sage_autodoc.py

@@ -3024,9 +3024,14 @@ def _get_property_getter(self) -> Callable | None:
 
 def autodoc_attrgetter(app: Sphinx, obj: Any, name: str, *defargs: Any) -> Any:
     """Alternative getattr() for types"""
-    for typ, func in app.registry.autodoc_attrgetters.items():
-        if isinstance(obj, typ):
-            return func(obj, name, *defargs)
+    try:
+        for typ, func in app.registry.autodoc_attrgetters.items():
+            if isinstance(obj, typ):
+                return func(obj, name, *defargs)
+    except AttributeError:
+        for typ, func in app.registry.autodoc_attrgettrs.items():
+            if isinstance(obj, typ):
+                return func(obj, name, *defargs)
 
     return safe_getattr(obj, name, *defargs)