Update docs

docs/topics/spider-middleware.rst

@@ -112,9 +112,8 @@ following methods:
 
     .. method:: process_spider_exception(response, exception, spider)
 
-        This method is called when when a spider or :meth:`process_spider_input`/
-        :meth:`process_spider_output` method (from other spider middleware)
-        raises an exception.
+        This method is called when a spider or :meth:`process_spider_output`
+        method (from a previous spider middleware) raises an exception.
 
         :meth:`process_spider_exception` should return either ``None`` or an
         iterable of :class:`~scrapy.http.Request`, dict or
@@ -126,7 +125,7 @@ following methods:
         exception reaches the engine (where it's logged and discarded).
 
         If it returns an iterable the :meth:`process_spider_output` pipeline
-        kicks in, starting with the last non-executed method, and no other
+        kicks in, starting from the next spider middleware, and no other
         :meth:`process_spider_exception` will be called.
 
         :param response: the response being processed when the exception was