Add note regarding RefCounted to EditorScript docs

(cherry picked from commit e5dc2ed98278575ca6d0cae68228995bbc386ada)

doc/classes/EditorScript.xml

@@ -15,6 +15,7 @@
 		    print("Hello from the Godot Editor!")
 		[/codeblock]
 		[b]Note:[/b] The script is run in the Editor context, which means the output is visible in the console window started with the Editor (stdout) instead of the usual Godot [b]Output[/b] dock.
+		[b]Note:[/b] EditorScript is reference counted, meaning it is destroyed when nothing references it. This can cause errors during asynchronous operations if there are no references to the script.
 	</description>
 	<tutorials>
 	</tutorials>