edit prediction: Context debug view (#38435)

Adds a `dev: open edit prediction context` action that opens a new
workspace pane that displays the excerpts and snippets that would be
included in the edit prediction request.

Release Notes:

- N/A

---------

Co-authored-by: Bennet <bennet@zed.dev>

crates/zed/src/main.rs

@@ -549,6 +549,7 @@ pub fn main() {
         language_models::init(app_state.user_store.clone(), app_state.client.clone(), cx);
         agent_settings::init(cx);
         acp_tools::init(cx);
+        edit_prediction_tools::init(cx);
         web_search::init(cx);
         web_search_providers::init(app_state.client.clone(), cx);
         snippet_provider::init(cx);