docs(*): add overlay change and arrange 11.0.0 changelog

Author: Lipata

CHANGELOG.md

@@ -3,9 +3,6 @@
 All notable changes for each version of this project will be documented in this file.
 ## 11.0.0
 
-### New Features
-- `IgxCalendar`
-    - Is now fully accessible to screen readers.
 
 ### General
 - `IgxGrid`, `IgxTreeGrid`, `IgxHierarchicalGrid`
@@ -18,6 +15,14 @@ All notable changes for each version of this project will be documented in this
 
         Refer to the official documentation for more information.
 
+### New Features
+- `IgxCalendar`
+    - Is now fully accessible to screen readers.
+
+### Improvements
+- `IgxOverlay`
+    - New functionality to automatically determine the correct animation that is needed when showing an overlay content. This is used with Auto Position strateгy, where the `IgxOverlay` content is flipped, depending on the available space.
+
 ## 10.2.0
 
 ### General