docs: update anywidget demo notebook with max columns feature

Author: shuoweil

notebooks/dataframes/anywidget_mode.ipynb

@@ -51,7 +51,8 @@
     "- **Rich DataFrames & Series:** Both DataFrames and Series are displayed as interactive widgets.\n",
     "- **Pagination:** Navigate through large datasets page by page without overwhelming the output.\n",
     "- **Column Sorting:** Click column headers to toggle between ascending, descending, and unsorted views. Use **Shift + Click** to sort by multiple columns.\n",
-    "- **Column Resizing:** Drag the dividers between column headers to adjust their width."
+    "- **Column Resizing:** Drag the dividers between column headers to adjust their width.\n",
+    "- **Max Columns Control:** Limit the number of displayed columns to improve performance and readability for wide datasets."
    ]
   },
   {
@@ -511,7 +512,10 @@
    "metadata": {},
    "source": [
     "### Adjustable Column Widths\n",
-    "You can easily adjust the width of any column in the table. Simply hover your mouse over the vertical dividers between column headers. When the cursor changes to a resize icon, click and drag to expand or shrink the column to your desired width. This allows for better readability and customization of your table view."
+    "You can easily adjust the width of any column in the table. Simply hover your mouse over the vertical dividers between column headers. When the cursor changes to a resize icon, click and drag to expand or shrink the column to your desired width. This allows for better readability and customization of your table view.\n",
+    "\n",
+    "### Control Maximum Columns\n",
+    "You can control the number of columns displayed in the widget using the **Max columns** dropdown in the footer. This is useful for wide DataFrames where you want to focus on a subset of columns or improve rendering performance. Options include 3, 5, 7, 10, 20, or All."
    ]
   },
   {