bug with subscripts and superscripts in 3D

As reported by @ellecj - the problem has a couple of layers…

If I try to make this plot:

Plotly.newPlot(gd, [
    {
      "type": "mesh3d",
      "y": [0, 1, 2],
      "x": [1, 2, 0],
      "z": [2, 0, 1],
      "i": [0],
      "j": [1],
      "k": [2]
    }
  ],
  {
    "title": "Triangle mesh",
    "scene": {
      "zaxis": {
        "title": "Z<sup>SUPER</sup><sub>SUB</sub>"
      }
    }
  })

I don’t see any super or subscripts:

And then if I do a relayout:

Plotly.relayout(gd, {'scene.zaxis.title':'ZZZ<sup>2</sup><sub>a</sub>'})

I see a superscript but not a subscript:

[archmoj]

Now in the PR #3207 the superscripts and subscripts could be used in webgl; and they are not limited to lower cases.

[etpinard]

cc @dfcreative