Improve handling of short lines in vertical motion algorithm
Improve handling of short lines in vertical motion algorithm

adrianheine/prosemirror,tzuhsiulin/prosemirror,kiejo/prosemirror,adrianheine/prosemirror,mattberkowitz/prosemirror,jacwright/prosemirror,kiejo/prosemirror,tecnogram888/prosemirror,tgecho/prosemirror,salzhrani/prosemirror,tzuhsiulin/prosemirror,mattberkowitz/prosemirror,ProseMirror/prosemirror-markdown,tecnogram888/prosemirror,tzuhsiulin/prosemirror,tgecho/prosemirror,adrianheine/prosemirror,bengler/prosemirror,kiejo/prosemirror,salzhrani/prosemirror,bengler/prosemirror,jacwright/prosemirror,salzhrani/prosemirror