docs: clarify routing callback execution

en/guide/routing.md

@@ -17,7 +17,7 @@ for example, `app.get()` to handle GET requests and `app.post` to handle POST re
 see [app.METHOD](/{{ page.lang }}/5x/api.html#app.METHOD). You can also use [app.all()](/{{ page.lang }}/5x/api.html#app.all) to handle all HTTP methods and [app.use()](/{{ page.lang }}/5x/api.html#app.use) to
 specify middleware as the callback function (See [Using middleware](/{{ page.lang }}/guide/using-middleware.html) for details).
 
-These routing methods specify a callback function (sometimes called "handler functions") called when the application receives a request to the specified route (endpoint) and HTTP method. In other words, the application "listens" for requests that match the specified route(s) and method(s), and when it detects a match, it calls the specified callback function.
+These routing methods specify a callback function (sometimes called a ‘handler function’) that Express automatically runs when the application receives a request matching the specified route (endpoint) and HTTP method. In other words, the application "listens" for requests that match the specified route(s) and method(s), and when it detects a match, it calls the specified callback function.
 
 In fact, the routing methods can have more than one callback function as arguments.
 With multiple callback functions, it is important to provide `next` as an argument to the callback function and then call `next()` within the body of the function to hand off control