include deprecated attributes in the reference

[alexcjohnson]

We track obsolete attributes in the schema, in a special _deprecated container - we should show these in the reference, with a prominent indication of this status. Their descriptions already mention what to do instead.

histogram[2d[contour]].autobin(x|y) is the latest to join the ranks of deprecated attributes https://github.com/plotly/plotly.js/pull/3044