REF: separate 2D only methods from ArrayManager (#40863)

Author: jbrockmendel

pandas/_typing.py

@@ -185,11 +185,11 @@
 ]
 
 # internals
-Manager = Union["ArrayManager", "BlockManager", "SingleBlockManager"]
+Manager = Union[
+    "ArrayManager", "SingleArrayManager", "BlockManager", "SingleBlockManager"
+]
 SingleManager = Union["SingleArrayManager", "SingleBlockManager"]
 Manager2D = Union["ArrayManager", "BlockManager"]
-# TODO: Manager2d excludes SingleBlockManager, but does not exclude
-#  SingleArrayManager
 
 # indexing
 # PositionalIndexer -> valid 1D positional indexer, e.g. can pass