Merge branch 'pb/log-rev-list-doc' into master

"git help log" has been enhanced by sharing more material from the documentation for the underlying "git rev-list" command. * pb/log-rev-list-doc: git-log.txt: include rev-list-description.txt git-rev-list.txt: move description to separate file git-rev-list.txt: tweak wording in set operations git-rev-list.txt: fix Asciidoc syntax revisions.txt: describe 'rev1 rev2 ...' meaning for ranges git-log.txt: add links to 'rev-list' and 'diff' docs