docs: discuss how quantitative is related to ratio and interval type of measurement (#5090)
docs: discuss how quantitative is related to ratio and interval type of measurement (#5090)

fix #4570
vega/vega-lite,vega/vega-lite,uwdata/vega-lite,uwdata/vega-lite,vega/vega-lite,uwdata/vega-lite,vega/vega-lite,uwdata/vega-lite,uwdata/vega-lite,vega/vega-lite