add timeout for process termination

Author: LykashevichAndrei

appium/webdriver/appium_service.py

@@ -229,7 +229,7 @@ def stop(self, timeout: int = 5) -> bool:
         or has been already stopped.
 
         Args:
-            timeout: timeout for process termination
+            timeout: timeout for process termination.
 
         Returns:
             `True` if the service was running before being stopped