refactor(single-instance): improve userdata ptr handling (#2453)

* fix(single-instance): fix null pointer dereference panic on Windows

* fmt

plugins/single-instance/examples/vanilla/src-tauri/build.rs

@@ -3,5 +3,5 @@
 // SPDX-License-Identifier: MIT
 
 fn main() {
-  tauri_build::build()
+    tauri_build::build()
 }

plugins/single-instance/examples/vanilla/src-tauri/rustfmt.toml

@@ -1,14 +0,0 @@
-max_width = 100
-hard_tabs = false
-tab_spaces = 2
-newline_style = "Auto"
-use_small_heuristics = "Default"
-reorder_imports = true
-reorder_modules = true
-remove_nested_parens = true
-edition = "2021"
-merge_derives = true
-use_try_shorthand = false
-use_field_init_shorthand = false
-force_explicit_abi = true
-imports_granularity = "Crate"

plugins/single-instance/examples/vanilla/src-tauri/src/main.rs

@@ -3,16 +3,15 @@
 // SPDX-License-Identifier: MIT
 
 #![cfg_attr(
-  all(not(debug_assertions), target_os = "windows"),
-  windows_subsystem = "windows"
+    all(not(debug_assertions), target_os = "windows"),
+    windows_subsystem = "windows"
 )]
 
 fn main() {
-  tauri::Builder::default()
-    .plugin(tauri_plugin_cli::init())
-    .plugin(tauri_plugin_single_instance::init(|app, argv, cwd| {
-      println!("{}, {argv:?}, {cwd}", app.package_info().name);
-    }))
-    .run(tauri::generate_context!())
-    .expect("error while running tauri application");
+    tauri::Builder::default()
+        .plugin(tauri_plugin_single_instance::init(|app, argv, cwd| {
+            println!("{}, {argv:?}, {cwd}", app.package_info().name);
+        }))
+        .run(tauri::generate_context!())
+        .expect("error while running tauri application");
 }