docs(CHANGES,MIGRATION): Note split window updates

Author: tony

CHANGES

@@ -15,6 +15,13 @@ $ pip install --user --upgrade --pre libtmux
 
 <!-- To maintainers and contributors: Please add notes for the forthcoming version above -->
 
+### Breaking changes
+
+Splitting updates (#532):
+
+- `Window.split_window()` to {meth}`Window.split()`
+- `Pane.split_window()` to {meth}`Pane.split()`
+
 ### Development
 
 - poetry: 1.7.1 -> 1.8.1

MIGRATION

@@ -25,6 +25,13 @@ _Detailed migration steps for the next version will be posted here._
 
 <!-- To the maintainers and contributors: please add migration details for the upcoming release here -->
 
+## 0.33.0: Deprecations for splitting (2024-03-03)
+
+### Deprecations (#532)
+
+- `Window.split_window()` to {meth}`Window.split()`
+- `Pane.split_window()` to {meth}`Pane.split()`
+
 ## 0.31.0: Renaming and command cleanup (2024-02-17)
 
 ### Cleanups (#527)