Allow an initial prompt to be associated with inline assist (#14816)

Release Notes:

- Added the ability to create custom inline assist bindings that
pre-fill a prompt from your keymap, e.g.:
    ```json
    [
        {
            "context": "Editor && mode == full",
            "bindings": {
                "ctrl-shift-enter": [
                    "assistant::InlineAssist",
                    { "prompt": "Build a snake game" }
                ]
            }
        }
    ]
    ```

---------

Co-authored-by: Nathan <nathan@zed.dev>

docs/src/SUMMARY.md

@@ -18,7 +18,7 @@
 # Using Zed
 
 - [Multibuffers](./multibuffers.md)
-- [Assistant Panel](./assistant-panel.md)
+- [Language model integration](./language-model-integration.md)
 - [Channels](./channels.md)
 - [Collaboration](./collaboration.md)
 - [Git](./git.md)