Add never option to scrollbar settings

crates/editor/src/element.rs

@@ -2064,6 +2064,7 @@ impl Element<Editor> for EditorElement {
             }
             settings::ShowScrollbars::System => editor.scroll_manager.scrollbars_visible(),
             settings::ShowScrollbars::Always => true,
+            settings::ShowScrollbars::Never => false,
         };
 
         let include_root = editor

crates/settings/src/settings.rs

@@ -76,6 +76,7 @@ pub enum ShowScrollbars {
     Auto,
     System,
     Always,
+    Never,
 }
 
 #[derive(Copy, Clone, Debug, Serialize, Deserialize, JsonSchema, PartialEq, Eq, Default)]