Sketch in assistant edit button (#19705)

Add an edit button to the assistant. This is totally hacked in for now,
just to see how this would feel rendered simply in the UI.

![CleanShot 2024-10-24 at 16 26
14@2x](https://github.com/user-attachments/assets/e630d078-78b7-42d7-93f1-cf61c00bd20e)

cc @as-cii @danilo-leal 

Release Notes:

- N/A

---------

Co-authored-by: Danilo Leal <67129314+danilo-leal@users.noreply.github.com>
Co-authored-by: Richard Feldman <oss@rtfeldman.com>

crates/assistant/src/terminal_inline_assistant.rs

@@ -1,6 +1,6 @@
 use crate::{
     humanize_token_count, prompts::PromptBuilder, AssistantPanel, AssistantPanelEvent,
-    ModelSelector, DEFAULT_CONTEXT_LINES,
+    ModelSelector, RequestType, DEFAULT_CONTEXT_LINES,
 };
 use anyhow::{Context as _, Result};
 use client::telemetry::Telemetry;
@@ -251,7 +251,7 @@ impl TerminalInlineAssistant {
                         .read(cx)
                         .active_context(cx)?
                         .read(cx)
-                        .to_completion_request(cx),
+                        .to_completion_request(RequestType::Chat, cx),
                 )
             })
         } else {