Demos.md for new components (DevExpress#6884)

Author: mpreyskurantov

concepts/05 UI Components/Chat/Demos.md

@@ -0,0 +1,5 @@
+#include demos-intro
+
+- [Overview](https://js.devexpress.com/Demos/WidgetsGallery/Demo/Chat/Overview/)
+- [Customization](https://js.devexpress.com/Demos/WidgetsGallery/Demo/Chat/Customization/)
+- [AI and Chatbot Integration](https://js.devexpress.com/Demos/WidgetsGallery/Demo/Chat/AIAndChatbotIntegration/)

concepts/05 UI Components/HtmlEditor/Demos.md

@@ -1,7 +1,7 @@
 #include demos-intro
 
 - [Overview](https://js.devexpress.com/Demos/WidgetsGallery/Demo/HtmlEditor/Overview/)
-- [Output Formats](https://js.devexpress.com/Demos/WidgetsGallery/Demo/HtmlEditor/OutputFormats/)
-- [Toolbar Customization](https://js.devexpress.com/Demos/WidgetsGallery/Demo/HtmlEditor/ToolbarCustomization/)
 - [Mentions](https://js.devexpress.com/Demos/WidgetsGallery/Demo/HtmlEditor/Mentions/)
 - [Tables](https://js.devexpress.com/Demos/WidgetsGallery/Demo/HtmlEditor/Tables/)
+- [Markdown Support](https://js.devexpress.com/Demos/WidgetsGallery/Demo/HtmlEditor/MarkdownSupport/)
+- [Toolbar Customization](https://js.devexpress.com/Demos/WidgetsGallery/Demo/HtmlEditor/ToolbarCustomization/)

concepts/05 UI Components/Pagination/Demos.md

@@ -0,0 +1,3 @@
+#include demos-intro
+
+- [Overview](https://js.devexpress.com/Demos/WidgetsGallery/Demo/Pagination/Overview/)