Use array_api as opposed to signatures for 2021.12 autodoc

Author: honno

spec/2021.12/conf.py

@@ -4,4 +4,4 @@
 from _array_api_conf import *
 
 release = "2021.12"
-sys.modules["signatures"] = stubs_mod
+sys.modules["array_api"] = stubs_mod

src/array_api_stubs/_2021_12/__init__.py

@@ -0,0 +1,14 @@
+from .array_object import *
+from .constants import *
+from .creation_functions import *
+from .data_type_functions import *
+from . import data_types as dtype
+from .elementwise_functions import *
+from .linear_algebra_functions import *
+from .manipulation_functions import *
+from .searching_functions import *
+from .set_functions import *
+from .sorting_functions import *
+from .statistical_functions import *
+from .utility_functions import *
+from . import linalg