Document question for "Request handling"

[lijiachuan1982]

In the request handling document https://github.com/hyperledger/indy-plenum/blob/master/docs/source/request_handling.md

There is one sentence "There are 3 types of requests a client can send", but below it only provides 2 types, so what is the 3rd type?

[Toktar]

The third type is action requests from indy-node. We need to add general description for action handlers. https://github.com/hyperledger/indy-node/blob/master/docs/source/requests.md#action-requests