Add user-visible output for remote operations (#25849)

This PR adds toasts for reporting success and errors from remote git
operations. This PR also adds a focus handle to notifications, in
anticipation of making them keyboard accessible.

Release Notes:

- N/A

---------

Co-authored-by: julia <julia@zed.dev>

crates/editor/src/code_context_menus.rs

@@ -514,7 +514,7 @@ impl CompletionsMenu {
                         );
 
                         let completion_label = StyledText::new(completion.label.text.clone())
-                            .with_highlights(&style.text, highlights);
+                            .with_default_highlights(&style.text, highlights);
                         let documentation_label = if let Some(
                             CompletionDocumentation::SingleLine(text),
                         ) = documentation