CLN: assorted (non-pytables) cleanups
includes a couple of whatsnew notes that fell through the cracks
@simonjayhawkins mypy is complaining about instantiating a class where we use abc.ABCMeta, thoughts? @gfyoung broke pieces off into #30006, #30007, will revert those from this PR > @simonjayhawkins mypy is complaining about instantiating a class where we use abc.ABCMeta, thoughts?

try this..

```diff
diff --git a/pandas/core/computation/engines.py b/pandas/core/computation/engines.py
index a4eaa897c..9b813bb4c 100644
--- a/pandas/core/computation/engines.py
+++ b/pandas/core/computation/engines.py
@@ -3,6 +3,7 @@ Engine classes for :func:`~pandas.eval`
 """
 
 import abc
+from typing import Dict, Type
 
 from pandas.core.computation.align import align_terms, reconstruct_object
 from pandas.core.computation.ops import _mathops, _reductions
@@ -139,4 +140,7 @@ class PythonEngine(AbstractEngine):
         pass
 
 
-_engines = {"numexpr": NumExprEngine, "python": PythonEngine}
+_engines: Dict[str, Type[AbstractEngine]] = {
+    "numexpr": NumExprEngine,
+    "python": PythonEngine,
+}
``` can you rebase thanks @jbrockmendel if you can address @gfyoung comment in a followup