Mark deprecated classes

example/lib/pages/home_page.dart

@@ -240,6 +240,7 @@ class _HomePageState extends State<HomePage> {
     return copiedFile.path.toString();
   }
 
+  // ignore: unused_element
   Future<MediaPickSetting?> _selectMediaPickSetting(BuildContext context) =>
       showDialog<MediaPickSetting>(
         context: context,

lib/src/widgets/toolbar.dart

@@ -410,6 +410,7 @@ class QuillToolbar extends StatelessWidget implements PreferredSizeWidget {
             dialogTheme: dialogTheme,
           ),
         if (showHorizontalRule)
+          // ignore: deprecated_member_use_from_same_package
           InsertEmbedButton(
             controller: controller,
             icon: Icons.horizontal_rule,

lib/src/widgets/toolbar/insert_embed_button.dart

@@ -5,6 +5,7 @@ import '../../models/themes/quill_icon_theme.dart';
 import '../controller.dart';
 import '../toolbar.dart';
 
+@Deprecated('This is for horizontal line and not supported')
 class InsertEmbedButton extends StatelessWidget {
   const InsertEmbedButton({
     required this.controller,

lib/src/widgets/toolbar/quill_dropdown_button.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 
+@Deprecated('Not being used')
 class QuillDropdownButton<T> extends StatefulWidget {
   const QuillDropdownButton({
     required this.child,
@@ -26,6 +27,7 @@ class QuillDropdownButton<T> extends StatefulWidget {
   _QuillDropdownButtonState<T> createState() => _QuillDropdownButtonState<T>();
 }
 
+// ignore: deprecated_member_use_from_same_package
 class _QuillDropdownButtonState<T> extends State<QuillDropdownButton<T>> {
   @override
   Widget build(BuildContext context) {

lib/src/widgets/toolbar/select_alignment_button.dart

@@ -84,6 +84,7 @@ class _SelectAlignmentButtonState extends State<SelectAlignmentButton> {
       mainAxisSize: MainAxisSize.min,
       children: List.generate(buttonCount, (index) {
         return Padding(
+          // ignore: prefer_const_constructors
           padding: EdgeInsets.symmetric(horizontal: !kIsWeb ? 1.0 : 5.0),
           child: ConstrainedBox(
             constraints: BoxConstraints.tightFor(

lib/src/widgets/toolbar/select_header_style_button.dart

@@ -67,6 +67,7 @@ class _SelectHeaderStyleButtonState extends State<SelectHeaderStyleButton> {
       mainAxisSize: MainAxisSize.min,
       children: List.generate(4, (index) {
         return Padding(
+          // ignore: prefer_const_constructors
           padding: EdgeInsets.symmetric(horizontal: !kIsWeb ? 1.0 : 5.0),
           child: ConstrainedBox(
             constraints: BoxConstraints.tightFor(