Add tsc watch task so we can run it when we use the new editor (#2435)
Add tsc watch task so we can run it when we use the new editor (#2435)


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