Article on Using the MeshDataTool suggests uses of tessellation and simplifying meshes, even though you can't do that with the MeshDataTool

**Your Godot version:**
3.2.3.Stable

**Issue description:**
Article on **Using the MeshDataTool** suggests uses of tessellation and simplifying meshes, even though you can't do that with the MeshDataTool. Unless these functions exists somewhere but then there is the error of them not being documented in the docs or API either.

*The MeshDataTool is not used to generate geometry. But it is helpful for dynamically altering geometry, for example if you want to write a script to tessellate, simplify, or deform meshes.*

**URL to the documentation page (if already existing):**
https://docs.godotengine.org/en/stable/tutorials/content/procedural_geometry/meshdatatool.html