added previous step for run sync blocks in documentation.
added previous step for run sync blocks in documentation.

dashevo/insight-api-dash,pnagurny/bitcore-node,martindale/bitcore,bitpay/bitcore,bitjson/bitcore,netanelkl/bitcore-node,martindale/bitcore,bitjson/bitcore,martindale/bitcore,bitjson/bitcore,martindale/bitcore,bitjson/bitcore,maraoz/bitcore-node,bitpay/bitcore,bitpay/bitcore,bitpay/bitcore