docs: Add changelog

Author: gadenbuie

CHANGELOG.md

@@ -15,13 +15,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 different ways (see #1845 for more details):
   * By adding a `.suggestion` CSS class to an HTML element (e.g., `<span class="suggestion">A suggestion</span>`)
   * Add a `data-suggestion` attribute to an HTML element, and set the value to the input suggestion text (e.g., `<span data-suggestion="Suggestion value">Suggestion link</span>`)
+  * To auto-submit the suggestion when clicked by the user, include the `.submit` class or the `data-suggestion-submit="true"` attribute on the HTML element.
 
 * Added a new `.add_sass_layer_file()` method to `ui.Theme` that supports reading a Sass file with layer boundary comments, e.g. `/*-- scss:defaults --*/`. This format [is supported by Quarto](https://quarto.org/docs/output-formats/html-themes-more.html#bootstrap-bootswatch-layering) and makes it easier to store Sass rules and declarations that need to be woven into Shiny's Sass Bootstrap files. (#1790)
 
 * The `ui.Chat()` component's `.on_user_submit()` decorator method now passes the user input to the decorated function. This makes it a bit more obvious how to access the user input inside the decorated function. See the new templates (mentioned below) for examples. (#1801)
 
 * `shiny create` includes new and improved `ui.Chat()` template options. Most of these templates leverage the new [`{chatlas}` package](https://posit-dev.github.io/chatlas/), our opinionated approach to interfacing with various LLM. (#1806)
 
+* The `ui.Chat()` component's `.update_user_input()` method gains `submit` and `focus` options that allow you to submit the input on behalf of the user and to choose whether the input receives focus after the update. (#1851)
+
 ### Bug fixes
 
 * `ui.Chat()` now correctly handles new `ollama.chat()` return value introduced in `ollama` v0.4. (#1787)