Update lawn-mower.md with returning state (#2280)

* Update lawn-mower.md with returning state

* Update lawn-mower.md sentence improvement

* add blog post

* Text update

Co-authored-by: Martin Hjelmare <marhje52@gmail.com>

* Text update from suggestion

Co-authored-by: G Johansson <goran.johansson@shiftit.se>

* Text update from suggestion

Co-authored-by: G Johansson <goran.johansson@shiftit.se>

* add link to documentation

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* change date to today

* address the nitpick

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Co-authored-by: Martin Hjelmare <marhje52@gmail.com>
Co-authored-by: G Johansson <goran.johansson@shiftit.se>

blog/2024-08-23-lawn-mower-activity-returning.md

@@ -0,0 +1,30 @@
+---
+author: Michael Arthur
+authorURL: https://github.com/mikey0000
+title: New returning type in LawnMowerActivity
+---
+
+As of Home Assistant Core 2024.9, integrations implementing `LawnMowerEntity` can indicate that their mower is returning to the dock by using the new `LawnMowerActivity.RETURNING` state.
+
+More details can be found in the [documentation](/docs/core/entity/lawn-mower#activities)
+
+## Example
+
+```python
+    async def async_dock(self) -> None:
+        """Start docking."""
+        self._attr_activity = LawnMowerActivity.RETURNING
+        self.async_write_ha_state()
+```
+
+or by returning `LawnMowerActivity.RETURNING` in the activity property of your `lawn_mower` entity.
+
+```python
+    @property
+    def activity(self) -> LawnMowerActivity:
+        """Return the state of the mower."""
+        mower = self.mower
+        if mower.state is RETURNING:
+            return LawnMowerActivity.RETURNING
+        ...
+```

docs/core/entity/lawn-mower.md

@@ -23,6 +23,7 @@ Properties should always only return information from memory and not do I/O (lik
 | `MOWING` | The lawn mower is currently mowing.
 | `DOCKED` | The lawn mower is done mowing and is currently docked.
 | `PAUSED` | The lawn mower was active and is now paused.
+| `RETURNING` | The lawn mower is returning to the dock.
 | `ERROR`  | The lawn mower encountered an error while active and needs assistance.
 
 ## Supported features