Type Alias EChartsSeriesType

The series types this adapter reads.

Three are the cartesian ones (tier 1 of xability/maidr#1195), three carry one magnitude per named thing (tier 2a), two hand over a set of magnitudes already computed (tier 2b), five carry a hierarchy or a graph (tier 3), pictorialBar is a bar wearing a symbol, themeRiver, parallel and radar own the chart but are read as a set of series, and boxplot hands over a five-number summary. Two of them are read without an outline, which grid.ts records. A type outside this union is refused by name, so gaining a reading later is a decision rather than an accident.

Kept in step with READ in converters.ts, which is what actually decides -- this type is the public statement of it, and test/adapters/echarts/cartesian.test.ts fails if the two stop agreeing.