[docs] fix component prototype header level
[docs] fix component prototype header level

dmarcos/aframe,aframevr/aframe,ngokevin/aframe,darkwing/aframe,mkungla/aframe,RSpace/aframe,fernandojsg/aframe,wizgrav/aframe,wizgrav/aframe,googlecreativelab/aframe,RSpace/aframe,jaxmolina/ar,ngokevin/aframe,chenzlabs/aframe,chenzlabs/aframe,jaxmolina/ar,weddingdj/aframe,fernandojsg/aframe,darkwing/aframe,googlecreativelab/aframe,mkungla/aframe,weddingdj/aframe,dmarcos/aframe,aframevr/aframe