Added the release notes MD file and corresponding node entry in the TOC.html file

Author: DeepakRajSundar

ej2-asp-core-mvc/Release-notes/31.1.21.md

@@ -7,7 +7,7 @@ documentation: ug
 
 # Essential Studio® for ##Platform_Name## - v31.1.21 Release Notes 
 
-{% include release-info.html date="##RELEASE-DATE##"  version="v31.1.21" passed="103560" failed="0" %}
+{% include release-info.html date="September 23, 2025"  version="v31.1.21" passed="103560" failed="0" %}
 
 {% directory path: _includes/release-notes/v31.1.21 %}