update dragOffsetNotifier documentation

Author: mtallenca

lib/src/editor/editor.dart

@@ -196,7 +196,7 @@ class QuillEditorState extends State<QuillEditor>
   QuillEditorConfig get configurations => widget.config;
   QuillEditorConfig get config => widget.config;
 
-  // The offset of the drag gesture - where to display the magnifier
+  /// {@macro drag_offset_notifier}
   final dragOffsetNotifier = isMobileApp ? ValueNotifier<Offset?>(null) : null;
 
   @override

lib/src/editor/raw_editor/raw_editor.dart

@@ -26,6 +26,7 @@ class QuillRawEditor extends StatefulWidget {
   final QuillController controller;
   final QuillRawEditorConfig config;
 
+  /// {@template drag_offset_notifier}
   /// dragOffsetNotifier - Only used on iOS and Android
   ///
   /// [QuillRawEditor] contains a gesture detector [EditorTextSelectionGestureDetector]
@@ -44,6 +45,7 @@ class QuillRawEditor extends StatefulWidget {
   /// the correct location (or hide the magnifier if null). [EditorTextSelectionOverlay] will
   /// use the value of the dragOffsetNotifier to hide the context menu when the magnifier is
   /// displayed and show the context menu when dragging is complete.
+  /// {@endtemplate}
   final ValueNotifier<Offset?>? dragOffsetNotifier;
 
   @override