docs(web): update changelog, add comments

@@ -12,6 +12,7 @@ Breaking changes:
 * The `autoResume` attribute has been removed from the `MobileScanner` widget.
   The controller already automatically resumes, so it had no effect.
 * Removed `MobileScannerCallback` and `MobileScannerArgumentsCallback` typedef.
+* [Web] Replaced `jsqr` library with `zxing-js` for full barcode support.
 
 Improvements:
 * Toggling the device torch now does nothing if the device has no torch, rather than throwing an error.
@@ -21,6 +22,9 @@ Features:
 * Added a new `placeholderBuilder` function to the `MobileScanner` widget to customize the preview placeholder.
 * Added `autoStart` parameter to MobileScannerController(). If set to false, controller won't start automatically.
 * Added `hasTorch` function on MobileScannerController(). After starting the controller, you can check if the device has a torch.
+* [Web] Added ability to use custom barcode scanning js libraries 
+  by extending `WebBarcodeReaderBase` class and changing `barCodeReader` property in `MobileScannerWebPlugin`
+
 
 Fixes:
 * Fixes the missing gradle setup for the Android project, which prevented gradle sync from working.

@@ -35,6 +35,17 @@ class MobileScannerWebPlugin {
 
   static final html.DivElement vidDiv = html.DivElement();
 
+  /// Represents barcode reader library.
+  /// Change this property if you want to use a custom implementation.
+  ///
+  /// Example of using the jsQR library:
+  /// void main() {
+  ///   if (kIsWeb) {
+  ///     MobileScannerWebPlugin.barCodeReader =
+  ///         JsQrCodeReader(videoContainer: MobileScannerWebPlugin.vidDiv);
+  ///   }
+  ///   runApp(const MaterialApp(home: MyHome()));
+  /// }
   static WebBarcodeReaderBase barCodeReader =
       ZXingBarcodeReader(videoContainer: vidDiv);
   StreamSubscription? _barCodeStreamSubscription;

@@ -20,6 +20,11 @@ class Code {
   external Uint8ClampedList get binaryData;
 }
 
+/// Barcode reader that uses jsQR library.
+/// jsQR supports only QR codes format.
+///
+/// Include jsQR to your index.html file:
+/// <script src="https://cdn.jsdelivr.net/npm/jsqr@1.4.0/dist/jsQR.min.js"></script>
 class JsQrCodeReader extends WebBarcodeReaderBase
     with InternalStreamCreation, InternalTorchDetection {
   JsQrCodeReader({required super.videoContainer});

@@ -134,6 +134,10 @@ extension JsZXingBrowserMultiFormatReaderExt
   external MediaStream? stream;
 }
 
+/// Barcode reader that uses zxing-js library.
+///
+/// Include zxing-js to your index.html file:
+/// <script type="text/javascript" src="https://unpkg.com/@zxing/library@0.19.1"></script>
 class ZXingBarcodeReader extends WebBarcodeReaderBase
     with InternalStreamCreation, InternalTorchDetection {
   late final JsZXingBrowserMultiFormatReader _reader =