clean whatsnew

Author: jreback

doc/source/whatsnew/v0.24.0.txt

@@ -12,8 +12,6 @@ New features
 
 Other Enhancements
 ^^^^^^^^^^^^^^^^^^
-- ``ExtensionArray`` has gained the abstract methods ``.dropna()`` and ``.append()``
-- ``ExtensionDtype`` has gained the ability to instantiate from string dtypes, e.g. ``decimal`` would instaniate a registered ``DecimalDtype``
 -
 -
 
@@ -23,6 +21,15 @@ Other Enhancements
 Backwards incompatible API changes
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+.. _whatsnew_0240.api.extension:
+
+ExtensionType Changes
+^^^^^^^^^^^^^^^^^^^^^
+
+- ``ExtensionArray`` has gained the abstract methods ``.dropna()`` and ``.append()``, and attribute ``array_type`` (:issue:`21185`)
+- ``ExtensionDtype`` has gained the ability to instantiate from string dtypes, e.g. ``decimal`` would instaniate a registered ``DecimalDtype`` (:issue:`21185`)
+- The ``ExtensionArray`` constructor, ``_from_sequence`` now take the keyword arg ``copy=False`` (:issue:`21185`)
+
 .. _whatsnew_0240.api.other:
 
 Other API Changes