[Docs] Clarify that rule = line segments  -- Fix #3325 (#3504)
[Docs] Clarify that rule = line segments  -- Fix #3325 (#3504)


vega/vega-lite,uwdata/vega-lite,uwdata/vega-lite,uwdata/vega-lite,uwdata/vega-lite,vega/vega-lite,uwdata/vega-lite,vega/vega-lite,vega/vega-lite,vega/vega-lite