added custom button widget in toolbar (#1272)

lib/src/models/themes/quill_custom_button.dart

@@ -6,6 +6,7 @@ class QuillCustomButton {
     this.iconColor,
     this.onTap,
     this.tooltip,
+    this.child,
   });
 
   ///The icon widget
@@ -17,6 +18,9 @@ class QuillCustomButton {
   ///The function when the icon is tapped
   final VoidCallback? onTap;
 
+  ///The customButton placeholder
+  final Widget? child;
+
   /// The button tooltip.
   final String? tooltip;
 }

lib/src/widgets/toolbar.dart

@@ -567,6 +567,12 @@ class QuillToolbar extends StatelessWidget implements PreferredSizeWidget {
             QuillDivider(axis,
                 color: sectionDividerColor, space: sectionDividerSpace),
         for (var customButton in customButtons)
+          if (customButton.child != null) ...[
+            InkWell(
+              onTap: customButton.onTap,
+              child: customButton.child,
+            ),
+          ] else ...[
             CustomButton(
               onPressed: customButton.onTap,
               icon: customButton.icon,
@@ -577,6 +583,7 @@ class QuillToolbar extends StatelessWidget implements PreferredSizeWidget {
               tooltip: customButton.tooltip,
             ),
           ],
+      ],
     );
   }