Fix assorted linux issues (#10061)

- Fix a bug where modifiers would be dispatched before they changed
- Add a secondary modifier
- Improve keybindings

Release Notes:

- N/A

crates/editor/src/editor_settings.rs

@@ -92,7 +92,8 @@ pub enum ShowScrollbar {
 #[serde(rename_all = "snake_case")]
 pub enum MultiCursorModifier {
     Alt,
-    Cmd,
+    #[serde(alias = "cmd", alias = "ctrl")]
+    CmdOrCtrl,
 }
 
 #[derive(Clone, Default, Serialize, Deserialize, JsonSchema)]