Add DelayMs type for settings (#40659)

Closes #40610

Release Notes:

- N/A

crates/workspace/src/item.rs

@@ -811,7 +811,7 @@ impl<T: Item> ItemHandle for Entity<T> {
                             let autosave = item.workspace_settings(cx).autosave;
 
                             if let AutosaveSetting::AfterDelay { milliseconds } = autosave {
-                                let delay = Duration::from_millis(milliseconds);
+                                let delay = Duration::from_millis(milliseconds.0);
                                 let item = item.clone();
                                 pending_autosave.fire_new(
                                     delay,

crates/workspace/src/workspace.rs

@@ -8799,8 +8799,9 @@ mod tests {
         item.update(cx, |item, cx| {
             SettingsStore::update_global(cx, |settings, cx| {
                 settings.update_user_settings(cx, |settings| {
-                    settings.workspace.autosave =
-                        Some(AutosaveSetting::AfterDelay { milliseconds: 500 });
+                    settings.workspace.autosave = Some(AutosaveSetting::AfterDelay {
+                        milliseconds: 500.into(),
+                    });
                 })
             });
             item.is_dirty = true;