entity.md has some some incorrect indentation

First of all, I would just like to say thank you for making this very useful documentation! 😄 I'm definitely going to recommend this to anyone looking to get into making MCPE add-ons. Second, I'd just like to point out that the entity.md's code example has incorrect indentation after the 2nd line. It's not that big of a deal, but I thought I'd point it out anyway. 😉 