Add neovide_confirm_quit option to confirm before quitting (#1247)

* Add g:neovide_confirm_quit which will ask before quitting

* more compact

* cargo fmt

src/bridge/ui_commands.rs

@@ -127,7 +127,11 @@ impl ParallelCommand {
     async fn execute(self, nvim: &Neovim<TxWrapper>) {
         match self {
             ParallelCommand::Quit => {
-                nvim.command("qa!").await.ok();
+                nvim.command(
+                    "if get(g:, 'neovide_confirm_quit', 0) == 1 | confirm qa | else | qa! | endif",
+                )
+                .await
+                .ok();
             }
             ParallelCommand::Resize { width, height } => nvim
                 .ui_try_resize(width.max(10) as i64, height.max(3) as i64)