Chat: add STT mentions to demo descriptions (#32831)

Author: vladaskorohodova

apps/demos/Demos/Chat/AIAndChatbotIntegration/description.md

@@ -15,4 +15,8 @@ The AI model outputs responses in Markdown, while the Chat requires HTML output.
 
 ## Default Caption Customization
 
-The Chat component in this demo displays modified captions when the conversation is empty. The demo uses [localization](/Documentation/Guide/Common/Localization/) techniques to alter built-in text.
+The Chat component in this demo displays modified captions when the conversation is empty. The demo uses [localization](/Documentation/Guide/Common/Localization/) techniques to alter built-in text.
+
+## Speech Recognition
+
+Users can enter voice-driven messages when [speechToTextEnabled](/Documentation/ApiReference/UI_Components/dxChat/Configuration/#speechToTextEnabled) is set to `true`. Our Chat component uses [Web Speech APIs](https://developer.mozilla.org/en-US/docs/Web/API/Web_Speech_API) for speech recognition. Use [speechToTextOptions](/Documentation/ApiReference/UI_Components/dxChat/Configuration/#speechToTextOptions) to define custom speech recognizer settings, handle related events, and customize the speech-to-text button appearance.

apps/demos/Demos/Chat/Overview/description.md

@@ -24,4 +24,8 @@ Each message includes information about the sender ([author](/Documentation/ApiR
 
 If a user enters a message, the Chat component raises the [messageEntered](/Documentation/ApiReference/UI_Components/dxChat/Configuration/#onMessageEntered) event. Use the event handler to process the message. For example, you can display the message in the message feed and send the message to the server for storage.
 
-When users start or complete text entry, our Chat component raises [typingStart](/Documentation/ApiReference/UI_Components/dxChat/Configuration/#onTypingStart) and [typingEnd](/Documentation/ApiReference/UI_Components/dxChat/Configuration/#onTypingEnd) events. Use these events to manage the [typingUsers](/Documentation/ApiReference/UI_Components/dxChat/Configuration/#typingUsers) array. The DevExtreme Chat uses this array to display a list of active users.
+When users start or complete text entry, our Chat component raises [typingStart](/Documentation/ApiReference/UI_Components/dxChat/Configuration/#onTypingStart) and [typingEnd](/Documentation/ApiReference/UI_Components/dxChat/Configuration/#onTypingEnd) events. Use these events to manage the [typingUsers](/Documentation/ApiReference/UI_Components/dxChat/Configuration/#typingUsers) array. The DevExtreme Chat uses this array to display a list of active users.
+
+## Speech Recognition
+
+Users can enter voice-driven messages when [speechToTextEnabled](/Documentation/ApiReference/UI_Components/dxChat/Configuration/#speechToTextEnabled) is set to `true`. Our Chat component uses [Web Speech APIs](https://developer.mozilla.org/en-US/docs/Web/API/Web_Speech_API) for speech recognition. Use [speechToTextOptions](/Documentation/ApiReference/UI_Components/dxChat/Configuration/#speechToTextOptions) to define custom speech recognizer settings, handle related events, and customize the speech-to-text button appearance.