Change ToolOutput to ToolView (#11682)

Additionally, the internal `ToolView` trait used by the registry is now
called `InternalToolView`.

This should make it a bit easier to understand that the `ToolView` is
intended for a `gpui::View` (implementing `Render`). It does still feel
like more could be merged here but I think the built tools are now a bit
clearer.

Release Notes:

- N/A

crates/assistant2/src/tools/create_buffer.rs

@@ -1,5 +1,5 @@
 use anyhow::{anyhow, Result};
-use assistant_tooling::{LanguageModelTool, ProjectContext, ToolOutput};
+use assistant_tooling::{LanguageModelTool, ProjectContext, ToolView};
 use editor::Editor;
 use gpui::{prelude::*, Model, Task, View, WeakView};
 use project::Project;
@@ -65,7 +65,7 @@ impl Render for CreateBufferView {
     }
 }
 
-impl ToolOutput for CreateBufferView {
+impl ToolView for CreateBufferView {
     type Input = CreateBufferInput;
 
     type SerializedState = ();