Streaming tool calls (#29179)

https://github.com/user-attachments/assets/7854a737-ef83-414c-b397-45122e4f32e8



Release Notes:

- Create file and edit file tools now stream their tool descriptions, so
you can see what they're doing sooner.

---------

Co-authored-by: Marshall Bowers <git@maxdeviant.com>

crates/language_models/src/provider/copilot_chat.rs

@@ -367,6 +367,7 @@ pub fn map_to_language_model_completion_events(
                                                 LanguageModelToolUse {
                                                     id: tool_call.id.into(),
                                                     name: tool_call.name.as_str().into(),
+                                                    is_input_complete: true,
                                                     input: serde_json::Value::from_str(
                                                         &tool_call.arguments,
                                                     )?,