Fallible Settings (#42938)

Also tidies up error notifications so that in the case of syntax errors
we don't see noise about the migration failing as well.

Release Notes:

- Invalid values in settings files will no longer prevent the rest of
the file from being parsed.

crates/zed/src/main.rs

@@ -50,8 +50,8 @@ use workspace::{
 use zed::{
     OpenListener, OpenRequest, RawOpenRequest, app_menus, build_window_options,
     derive_paths_with_position, edit_prediction_registry, handle_cli_connection,
-    handle_keymap_file_changes, handle_settings_changed, handle_settings_file_changes,
-    initialize_workspace, open_paths_with_positions,
+    handle_keymap_file_changes, handle_settings_file_changes, initialize_workspace,
+    open_paths_with_positions,
 };
 
 use crate::zed::{OpenRequestKind, eager_load_active_theme_and_icon_theme};
@@ -411,12 +411,7 @@ pub fn main() {
         }
         settings::init(cx);
         zlog_settings::init(cx);
-        handle_settings_file_changes(
-            user_settings_file_rx,
-            global_settings_file_rx,
-            cx,
-            handle_settings_changed,
-        );
+        handle_settings_file_changes(user_settings_file_rx, global_settings_file_rx, cx);
         handle_keymap_file_changes(user_keymap_file_rx, cx);
 
         let user_agent = format!(