minor: DesignForExtension documentation update
minor: DesignForExtension documentation update

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