docs(features): Add single instance page

src/content/docs/features/single-instance.mdx

@@ -1,14 +1,76 @@
 ---
 title: Single Instance
-description: Ensure a single instance of your tauri app is running.
+description: Plugin to ensure that a single instance of your tauri app is running at a time.
 ---
 
-import Stub from '@components/Stub.astro';
 import PluginLinks from '@components/PluginLinks.astro';
+import { Tabs, TabItem } from '@astrojs/starlight/components';
 
 <PluginLinks plugin="single-instance" showJsLinks={false} />
 
-<Stub>
-	Based on
-	https://github.com/tauri-apps/plugins-workspace/tree/v2/plugins/single-instance
-</Stub>
+Plugin to ensure that a single instance of your tauri app is running at a time.
+
+
+## Install
+
+_This plugin requires a Rust version of at least **1.75**_
+
+You can install the Core plugin by adding the following to your `Cargo.toml` file:
+
+<Tabs>
+  <TabItem label="crates.io">
+```toml title="src-tauri/Cargo.toml" ins={2}
+[dependencies]
+tauri-plugin-single-instance = "2.0.0-beta"
+```
+  </TabItem>
+  <TabItem label="Git">
+
+```toml title="src-tauri/Cargo.toml" ins={2}
+[dependencies]
+tauri-plugin-single-instance = { git = "https://github.com/tauri-apps/plugins-workspace", branch = "v2" }
+```
+  </TabItem>
+</Tabs>
+
+## Usage
+
+To use this plugin, you need to register the core plugin with Tauri. The plugin init() method takes a closure that is called when a new app instance was started, but closed by the plugin. The closure has three arguments: the AppHandle, the list of arguments (important for instance on deep link usage) and the current working directory:
+
+```rust title="src-tauri/src/main.rs" ins={3}
+fn main() {
+    tauri::Builder::default()
+        .plugin(tauri_plugin_single_instance::init(|app, args, cwd| {}))
+        .run(tauri::generate_context!())
+        .expect("error while running tauri application");
+}
+```
+
+### Focusing on New Instance
+
+By default nothing happens when you start a new instance and the application is already running. To focus the window of the running instance when user tries to open a new instance, change the callback closure:
+
+
+```rust title="src-tauri/src/main.rs" {1} {5-7} {12-21}
+use tauri::{AppHandle, Manager};
+
+fn main() {
+    tauri::Builder::default()
+        .plugin(tauri_plugin_single_instance::init(|app, args, cwd| {
+            let _ = show_window(app);
+        }))
+        .run(tauri::generate_context!())
+        .expect("error while running tauri application");
+}
+
+fn show_window(app: &AppHandle) {
+    let windows = app.webview_windows();
+
+    windows
+        .values()
+        .next()
+        .expect("Sorry, no window found")
+        .set_focus()
+        .expect("Can't Bring Window to Focus");
+}
+```