doc: release notes 7.8
doc: release notes 7.8

checkstyle/checkstyle,liscju/checkstyle,rnveach/checkstyle,romani/checkstyle,sharang108/checkstyle,checkstyle/checkstyle,sharang108/checkstyle,jonmbake/checkstyle,rnveach/checkstyle,rnveach/checkstyle,romani/checkstyle,checkstyle/checkstyle,checkstyle/checkstyle,jonmbake/checkstyle,sabaka/checkstyle,sabaka/checkstyle,liscju/checkstyle,romani/checkstyle,rnveach/checkstyle,sabaka/checkstyle,sharang108/checkstyle,checkstyle/checkstyle,romani/checkstyle,liscju/checkstyle,jonmbake/checkstyle,jochenvdv/checkstyle,checkstyle/checkstyle,rnveach/checkstyle,jochenvdv/checkstyle,jochenvdv/checkstyle,rnveach/checkstyle,romani/checkstyle,romani/checkstyle