Originally reported by @slinstj in main Yii2 repo yiisoft/yii2#16202

What steps will reproduce the problem?

1. Access the guide section in website;
2. Look at the search field. It says: "Search Guide..."
   
3. Now, try to search a "Guide" section, maybe "Rest":
   

What is the expected result?

It should give us the Guide results.

What do you get instead?

Everything (Api and others) except Guide results.

What could be done?

Either change the placeholder text or really include Guide results on it.

Additional info

Google Chrome [Versão 66.0.3359.139 (Versão oficial) 64 bits]
Ubuntu 18.04