added warnings about line height attribute could cause conflicts with original Quill API

doc/custom_toolbar.md

@@ -73,6 +73,14 @@ QuillToolbar.simple(
           isBackground: true,
         ),
         const VerticalDivider(),
+        // This is an implementation that only is used on
+        // flutter_quill and it's not originally 
+        // implemented in Quill JS API, so it could cause conflicts
+        // with the original Quill Delta format
+        QuillToolbarSelectLineHeightStyleDropdownButton(
+          controller: globalController,
+        ),
+        const VerticalDivider(),
         QuillToolbarSelectHeaderStyleButton(
           controller: controller,
         ),

lib/src/models/config/toolbar/simple_toolbar_configurations.dart

@@ -191,7 +191,6 @@ class QuillSimpleToolbarConfigurations extends QuillSharedToolbarProperties {
   final bool showUnderLineButton;
   final bool showStrikeThrough;
   final bool showInlineCode;
-  final bool showLineHeightButton;
   final bool showColorButton;
   final bool showBackgroundColorButton;
   final bool showClearFormat;
@@ -219,6 +218,10 @@ class QuillSimpleToolbarConfigurations extends QuillSharedToolbarProperties {
   final bool showClipboardCopy;
   final bool showClipboardPaste;
 
+  /// This activates a functionality that is only implemented in [flutter_quill] and is NOT originally 
+  /// used in the [Quill Js API]. So it could cause conflicts if you use this attribute with the original Delta format of Quill Js 
+  final bool showLineHeightButton;
+
   /// Toolbar items to display for controls of embed blocks
   final List<EmbedButtonBuilder>? embedButtons;