expected precision field of Projection to be a number not a string in VegaLite 3.3.0 schema

[DougBurke]

I was surprised to find the precision field of Projection has a type of string and not number:

https://github.com/vega/schema/blob/master/vega-lite/v3.3.0.json#L8971

        "precision": {
          "description": "Sets the threshold for the projection’s [adaptive resampling](http://bl.ocks.org/mbostock/3795544) to the specified value in pixels. This value corresponds to the [Douglas–Peucker distance](http://en.wikipedia.org/wiki/Ramer%E2%80%93Douglas%E2%80%93Peucker_algorithm). If precision is not specified, returns the projection’s current resampling precision which defaults to `√0.5 ≅ 0.70710…`.",
          "type": "string"
},

[domoritz]

Looks like Vega expects strings: https://vega.github.io/vega/docs/projections/

[DougBurke]

I wonder why? Oh well, thanks for checking.

[domoritz]

Well, could be a bug in Vega. Could you check?

[domoritz]

The Vega schema says it's number: https://github.com/vega/vega/blob/master/packages/vega-schema/src/projection.js#L20.

[DougBurke]

Sorry - was in a meeting so couldn't investigate further.

[domoritz]

No problem. Again, thanks for catching and reporting the issue! I fixed it in #5191.