agent: Add several UX improvements (#29828)

Still a work in progress.

Release Notes:

- N/A

---------

Co-authored-by: Bennet Bo Fenner <bennetbo@gmx.de>
Co-authored-by: Nathan Sobo <nathan@zed.dev>
Co-authored-by: Cole Miller <m@cole-miller.net>
Co-authored-by: Nathan Sobo <1789+nathansobo@users.noreply.github.com>
Co-authored-by: Cole Miller <53574922+cole-miller@users.noreply.github.com>

crates/assistant/src/terminal_inline_assistant.rs

@@ -5,7 +5,7 @@ use assistant_settings::AssistantSettings;
 use client::telemetry::Telemetry;
 use collections::{HashMap, VecDeque};
 use editor::{
-    Editor, EditorElement, EditorEvent, EditorMode, EditorStyle, MultiBuffer,
+    ContextMenuOptions, Editor, EditorElement, EditorEvent, EditorMode, EditorStyle, MultiBuffer,
     actions::{MoveDown, MoveUp, SelectAll},
 };
 use fs::Fs;
@@ -730,6 +730,11 @@ impl PromptEditor {
             );
             editor.set_soft_wrap_mode(language::language_settings::SoftWrap::EditorWidth, cx);
             editor.set_placeholder_text(Self::placeholder_text(window, cx), cx);
+            editor.set_context_menu_options(ContextMenuOptions {
+                min_entries_visible: 12,
+                max_entries_visible: 12,
+                placement: None,
+            });
             editor
         });