doc: update readme

@@ -11,11 +11,12 @@ A universal barcode and QR code scanner for Flutter based on MLKit. Uses CameraX
 | :-----: | :-: | :---: | :-: | :---: | :-----: |
 |   ✔️    | ✔️   |  ✔️  |   |     |      |
 
-Android: SDK 21 and newer. Reason: CameraX requires at least SDK 21.
-iOS: iOS 11 and newer. Reason: MLKit for iOS requires at least iOS 11 and a [64bit device](https://developers.google.com/ml-kit/migration/ios).
-macOS: macOS 10.13. Reason: Apple Vision library.
+### Android
+SDK 21 and newer. Reason: CameraX requires at least SDK 21.
 
 ### iOS
+iOS 11 and newer. Reason: MLKit for iOS requires at least iOS 11 and a [64bit device](https://developers.google.com/ml-kit/migration/ios).
+
 Add the following keys to your Info.plist file, located in <project root>/ios/Runner/Info.plist:
 
 NSCameraUsageDescription - describe why your app needs access to the camera. This is called Privacy - Camera Usage Description in the visual editor.
@@ -23,13 +24,16 @@ NSCameraUsageDescription - describe why your app needs access to the camera. Thi
 If you want to use the local gallery feature from [image_picker](https://pub.dev/packages/image_picker)
 NSPhotoLibraryUsageDescription - describe why your app needs permission for the photo library. This is called Privacy - Photo Library Usage Description in the visual editor.
   
-## Feature Support
+### macOS
+macOS 10.13 or newer. Reason: Apple Vision library.
+
+## Features Supported
 
 | Features               | Android            | iOS                | macOS | Web |
 |------------------------|--------------------|--------------------|-------|-----|
 | analyzeImage (Gallery) | :heavy_check_mark: | :heavy_check_mark: |   :x:    |  :x:   |
 
-# Usage
+## Usage
 
 Import `package:mobile_scanner/mobile_scanner.dart`, and use the widget with or without the controller.