add 0.24.0 changelog entry

Author: rmorshea

docs/source/changelog.rst

@@ -1,6 +1,34 @@
 Changelog
 =========
 
+0.24.0
+------
+
+This release contains an update that allows components and elements to have "identity".
+That is, their state can be preserved across updates. Before this point, only the state
+for the component at the root of an update was preserved. Now though, the state for any
+component and element with a ``key`` that is unique amongst its siblings, will be
+preserved so long as this is also true for parent elements/components within the scope
+of the current update. Thus, only when the key of the element or component changes will
+its state do the same.
+
+In a future update, the default key for all elements and components will be its index
+with respect to its siblings in the layout. The
+:attr:`~idom.config.IDOM_FEATURE_INDEX_AS_DEFAULT_KEY` feature flag has been introduced
+to allow users to enable this behavior early.
+
+- add feature flag for default key behavior - `42ee01c <https://github.com/idom-team/idom/commit/42ee01c>`__
+- use unique object instead of index as default key - `5727ab4 <https://github.com/idom-team/idom/commit/5727ab4>`__
+- make HookCatcher/StaticEventHandlers testing utils - `1abfd76 <https://github.com/idom-team/idom/commit/1abfd76>`__
+- add element and component identity - `5548f02 <https://github.com/idom-team/idom/commit/5548f02>`__
+- minor doc updates - `e5511d9 <https://github.com/idom-team/idom/commit/e5511d9>`__
+- add tests for callback identity preservation with keys - `72e03ec <https://github.com/idom-team/idom/commit/72e03ec>`__
+- add 'key' to VDOM spec - `c3236fe <https://github.com/idom-team/idom/commit/c3236fe>`__
+- Rename validate_serialized_vdom to validate_vdom - `d04faf9 <https://github.com/idom-team/idom/commit/d04faf9>`__
+- EventHandler should not serialize itself - `f7a59f2 <https://github.com/idom-team/idom/commit/f7a59f2>`__
+- fix docs typos - `42b2e20 <https://github.com/idom-team/idom/commit/42b2e20>`__
+- fixes: #331 - add roadmap to docs - `4226c12 <https://github.com/idom-team/idom/commit/4226c12>`__
+
 0.23.1
 ------
 

src/idom/config.py

@@ -59,7 +59,7 @@
     mutable=False,
     validator=lambda x: bool(int(x)),
 )
-"""A feature flag for using the index of a sibling element as its default key
+"""Use the index of elements/components amongst their siblings as the default key.
 
 In a future release this flag's default value will be set to true, and after that, this
 flag will be removed entirely and the indices will always be the default key.