Add maxSamples property of renderer.capabilities to Docs

[ben4d85]

Is your feature request related to a problem? Please describe.

When console logging renderer.capabilities, the resulting object contains a property maxSamples: 8.

This property appears to be missing from the docs, see https://threejs.org/docs/#api/en/renderers/WebGLRenderer.capabilities

Describe the solution you'd like

Add the property to the docs and explain what it is for.

Additional context

I assume the maxSamples property is related to the (fairly new) ability to set the samples property of a WebGLRenderTarget (which only works for WebGL 2). It would be great to see this in the docs.