Sankey arrows example

doc/python/sankey-diagram.md

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   plotly:
     description: How to make Sankey Diagrams in Python with Plotly.
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@@ -210,6 +210,33 @@ fig = go.Figure(go.Sankey(
 fig.show()
 ```
 
+### Sankey Diagram with Arrow Links
+
+*New in 5.10*
+
+Create a Sankey diagram with arrow links by setting the `arrowlen` attribute of `link`:
+
+```python
+import plotly.graph_objects as go
+
+fig = go.Figure(go.Sankey(
+    arrangement = "snap",
+    node = dict(
+        label = ["A", "B", "C", "D", "E", "F"],
+        x = [0.2, 0.1, 0.5, 0.7, 0.3, 0.5],
+        y = [0.7, 0.5, 0.2, 0.4, 0.2, 0.3],
+        pad = 10  
+    ),
+    link = dict(
+        arrowlen = 15,
+        source = [0, 0, 1, 2, 5, 4, 3, 5],
+        target = [5, 3, 4, 3, 0, 2, 2, 3],
+        value = [1, 2, 1, 1, 1, 1, 1, 2]  
+    )))
+
+fig.show()
+```
+
 ### Reference
 
 See [https://plotly.com/python/reference/sankey](https://plotly.com/python/reference/sankey/) for more information and options!