[doc] Add REST API link into tutorials. (#6563)
[doc] Add REST API link into tutorials. (#6563)

* Add REST API link into tutorials.

* Move down section

* Add scala note.

aradchykov/playframework,playframework/playframework,marcospereira/playframework,richdougherty/playframework,aradchykov/playframework,ktoso/playframework,wegtam/playframework,ktoso/playframework,wsargent/playframework,rajeshpg/playframework,aradchykov/playframework,playframework/playframework,richdougherty/playframework,benmccann/playframework,Shenker93/playframework,richdougherty/playframework,benmccann/playframework,wegtam/playframework,wegtam/playframework,zaneli/playframework,mkurz/playframework,aradchykov/playframework,ktoso/playframework,hagl/playframework,Shruti9520/playframework,zaneli/playframework,benmccann/playframework,richdougherty/playframework,mkurz/playframework,hagl/playframework,zaneli/playframework,mkurz/playframework,Shruti9520/playframework,hagl/playframework,mkurz/playframework,marcospereira/playframework,marcospereira/playframework,rajeshpg/playframework,wsargent/playframework,playframework/playframework,rajeshpg/playframework,wegtam/playframework,rajeshpg/playframework,wsargent/playframework,benmccann/playframework,Shruti9520/playframework,Shenker93/playframework,Shruti9520/playframework,marcospereira/playframework,ktoso/playframework,Shenker93/playframework,Shenker93/playframework,hagl/playframework,wsargent/playframework,zaneli/playframework