Option to auto-close deleted files with no unsaved edits (#31920)

Closes #27982

Release Notes:

- Added `close_on_file_delete` setting (off by default) to allow closing
open files after they have been deleted on disk

---------

Co-authored-by: Bennet Bo Fenner <bennetbo@gmx.de>

crates/image_viewer/src/image_viewer.rs

@@ -11,7 +11,7 @@ use gpui::{
     InteractiveElement, IntoElement, ObjectFit, ParentElement, Render, Styled, Task, WeakEntity,
     Window, canvas, div, fill, img, opaque_grey, point, size,
 };
-use language::File as _;
+use language::{DiskState, File as _};
 use persistence::IMAGE_VIEWER;
 use project::{ImageItem, Project, ProjectPath, image_store::ImageItemEvent};
 use settings::Settings;
@@ -191,6 +191,10 @@ impl Item for ImageView {
             focus_handle: cx.focus_handle(),
         }))
     }
+
+    fn has_deleted_file(&self, cx: &App) -> bool {
+        self.image_item.read(cx).file.disk_state() == DiskState::Deleted
+    }
 }
 
 fn breadcrumbs_text_for_image(project: &Project, image: &ImageItem, cx: &App) -> String {