reverts v0.22 and fixes code blocks and typos in v0.23

Author: datajanko

doc/source/whatsnew/v0.23.0.txt

@@ -181,11 +181,11 @@ Please note that the string `index` is not supported with the round trip format,
 ``.assign()`` accepts dependent arguments
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-The :func:`DataFrame.assign()` now accepts dependent kwargs. In earlier versions this throws a Keyerror exception anymore. (:issue: `14207)
+The :func:`DataFrame.assign()` now accepts dependent kwargs. (:issue: `14207)
 
-Specifically, defining a new column inside assign may be referenced in the same assign statement if a callable is used. For example
+Specifically, defining a new column inside ``.assign()`` may be referenced in the same assign statement if a callable is used. For example
 
-.. code-block:: ipython     
+.. ipython:: python     
 
     In [3]: df = pd.DataFrame({'A': [1, 2, 3]})
 
@@ -199,8 +199,10 @@ Specifically, defining a new column inside assign may be referenced in the same
 .. warning::
 
 This may subtly change the behavior of your code when you're
-using ``assign`` to update an existing column. Previously, callables
-refering to other variables being updated would get the "old" values
+using ``.assign()`` to update an existing column. Previously, callables
+referring to other variables being updated would get the "old" values
+
+Previous Behaviour:
 
 .. code-block:: ipython
 
@@ -213,9 +215,9 @@ refering to other variables being updated would get the "old" values
     1  3 -2
     2  4 -3
 
-Now, callables will get the "new" value
+New Behaviour:
 
-.. code-block:: ipython
+.. ipython:: python
 
 
     In [4]: df = pd.DataFrame({"A": [1, 2, 3]})