Docs: Ensure the geometry browser uses BufferGeometry

[Mugen87]

The easiest approach to ensure BufferGeometry is passed to the renderer.

[mrdoob]

Wouldn't it be better to show a error in the console instead so we can fix the code?

[Mugen87]

The problem is that fixing the code would mean to change e.g. the usage of BoxGeometry to BoxBufferGeometry. In this context there is somewhat an inconsistency since a documentation page about BoxGeometry would directly create a BoxBufferGeometry. I thought we can clean this up if we change the geometry generators at some point like suggested here 😇: #15387 (comment)

[mrdoob]

I see I see. Can we console.log it for now then? It's just so we don't forget about it.

[Mugen87]

Okay, I'll make a PR 👍