Update sum_distinct explanation with bullet points and ignored value note

Generated-By: mintlify-agent

Author: mintlify[bot]

references/metrics.mdx

@@ -907,7 +907,17 @@ Consider a model containing `order_id`, `order_item_id`, and `order_shipping_cos
 | 2 🟩     | 5             | 20                  |
 | 2 🟩     | 6             | 30                  |
 
-If you want to sum shipping costs for all orders, you need to deduplicate by `order_id`. When `order_id` is the distinct key, the first `order_shipping_cost` in ascending order will be taken for each order. In this example, order 1 🟦 contributes 10 and order 2 🟩 contributes 20 (the first value when ordered ascending), giving a total of 30:
+To sum shipping costs for all orders, you need to deduplicate by `order_id`:
+
+- When `order_id` is the distinct key, the first `order_shipping_cost` in ascending order is taken for each order
+- Order 1 🟦 contributes **10**
+- Order 2 🟩 contributes **20** (the first value when ordered ascending)
+- The `order_shipping_cost` of **30** for order 2 is ignored
+- **Total: 30**
+
+<Note>
+If the value you are aggregating is truly distinct based on the distinct key (e.g., each order has only one shipping cost), this won't be a problem. However, if there are multiple different values for the same distinct key, only the first value in ascending order will be used.
+</Note>
 
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   <Tab title="dbt v1.9 and earlier">