chore: update documentation

plugins/barcode-scanner/src/error.rs

@@ -4,12 +4,17 @@
 
 use serde::{ser::Serializer, Serialize};
 
+/// Alias for the result type returned by this crate's functions.
 pub type Result<T> = std::result::Result<T, Error>;
 
+/// The error type returned by this crate's APIs. Serialized as its [`Display`](std::fmt::Display)
+/// string when it crosses the IPC boundary.
 #[derive(Debug, thiserror::Error)]
 pub enum Error {
+    /// An I/O error occurred.
     #[error(transparent)]
     Io(#[from] std::io::Error),
+    /// Failed to run a command on the mobile plugin implementation (Kotlin on Android, Swift on iOS).
     #[cfg(mobile)]
     #[error(transparent)]
     PluginInvoke(#[from] tauri::plugin::mobile::PluginInvokeError),

plugins/barcode-scanner/src/lib.rs

@@ -2,6 +2,10 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-License-Identifier: MIT
 
+//! Scan QR codes, EAN-13 and other kinds of barcodes with the device's camera.
+//!
+//! - Supported platforms: Android and iOS.
+
 #![cfg(mobile)]
 
 use tauri::{
@@ -29,6 +33,7 @@ impl<R: Runtime> BarcodeScanner<R> {}
 
 /// Extensions to [`tauri::App`], [`tauri::AppHandle`], [`tauri::WebviewWindow`], [`tauri::Webview`] and [`tauri::Window`] to access the barcode scanner APIs.
 pub trait BarcodeScannerExt<R: Runtime> {
+    /// Returns the [`BarcodeScanner`] instance managed by the app.
     fn barcode_scanner(&self) -> &BarcodeScanner<R>;
 }