Make common practices sample code match the comments

docs/topics/practices.rst

@@ -61,7 +61,7 @@ project as example.
     process = CrawlerProcess(get_project_settings())
 
     # 'followall' is the name of one of the spiders of the project.
-    process.crawl('testspider', domain='scrapinghub.com')
+    process.crawl('followall', domain='scrapinghub.com')
     process.start() # the script will block here until the crawling is finished
 
 There's another Scrapy utility that provides more control over the crawling