docs: fix title in quantile docs (#6871)
docs: fix title in quantile docs (#6871)


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