doc: release notes for 6.17
doc: release notes for 6.17

sharang108/checkstyle,jonmbake/checkstyle,checkstyle/checkstyle,sabaka/checkstyle,jonmbake/checkstyle,nikhilgupta23/checkstyle,rnveach/checkstyle,sirdis/checkstyle,izishared/checkstyle,MEZk/checkstyle,nikhilgupta23/checkstyle,HubSpot/checkstyle,ilanKeshet/checkstyle,vboerchers/checkstyle,sirdis/checkstyle,liscju/checkstyle,checkstyle/checkstyle,izishared/checkstyle,jochenvdv/checkstyle,sharang108/checkstyle,AkshitaKukreja30/checkstyle,romani/checkstyle,liscju/checkstyle,rnveach/checkstyle,checkstyle/checkstyle,bansalayush/checkstyle,checkstyle/checkstyle,romani/checkstyle,AkshitaKukreja30/checkstyle,checkstyle/checkstyle,ilanKeshet/checkstyle,romani/checkstyle,baratali/checkstyle,izishared/checkstyle,jonmbake/checkstyle,bansalayush/checkstyle,MEZk/checkstyle,sabaka/checkstyle,HubSpot/checkstyle,AkshitaKukreja30/checkstyle,rnveach/checkstyle,baratali/checkstyle,sharang108/checkstyle,romani/checkstyle,ilanKeshet/checkstyle,bansalayush/checkstyle,MEZk/checkstyle,romani/checkstyle,baratali/checkstyle,sirdis/checkstyle,romani/checkstyle,checkstyle/checkstyle,rnveach/checkstyle,jochenvdv/checkstyle,jochenvdv/checkstyle,vboerchers/checkstyle,rnveach/checkstyle,nikhilgupta23/checkstyle,rnveach/checkstyle,sabaka/checkstyle,liscju/checkstyle,vboerchers/checkstyle,HubSpot/checkstyle