Update 03.coding_the_player.rst

change _on_body_entered(body) to _on_body_entered(_body) to avoid warnings

getting_started/first_2d_game/03.coding_the_player.rst

@@ -489,7 +489,7 @@ this code to the function:
 .. tabs::
  .. code-tab:: gdscript GDScript
 
-    func _on_body_entered(body):
+    func _on_body_entered(_body):
         hide() # Player disappears after being hit.
         hit.emit()
         # Must be deferred as we can't change physics properties on a physics callback.