add link for developer-notes in contributing (#2260)
add link for developer-notes in contributing (#2260)


dashpay/dash,thelazier/dash,nmarley/dash,biblepay/biblepay,UdjinM6/dash,thelazier/dash,biblepay/biblepay,UdjinM6/dash,nmarley/dash,ionomy/ion,biblepay/biblepay,nmarley/dash,nmarley/dash,ionomy/ion,ionomy/ion,biblepay/biblepay,ionomy/ion,UdjinM6/dash,UdjinM6/dash,thelazier/dash,thelazier/dash,UdjinM6/dash,biblepay/biblepay,biblepay/biblepay,thelazier/dash,biblepay/biblepay,nmarley/dash,ionomy/ion,dashpay/dash,dashpay/dash,dashpay/dash,biblepay/biblepay,nmarley/dash,ionomy/ion,dashpay/dash,nmarley/dash