Update src/content/docs/durable-objects/concepts/durable-object-lifecycle.mdx

Author: Oxyjun

src/content/docs/durable-objects/concepts/durable-object-lifecycle.mdx

@@ -68,5 +68,5 @@ Objects in the **hibernated** state keep their Websocket clients connected, and
 The next incoming request or event starts the cycle again.
 
 :::note[Lifecycle states incurring duration charges]
-A Durable Object incurs charges only when it is **actively running in-memory**, or when it is **idle in-memory and non-hibernateable**.
+A Durable Object incurs charges only when it is **actively running in-memory**, or when it is **idle in-memory and non-hibernateable** (indicated as green rectangles in the diagram).
 :::