Fix misleading description of MeshDataTool.get_vertex() method

[mateuseap]

What I did

• Adjusted the description of MeshDataTool.get_vertex() method.

Closes: #80244

[fire]

Can also be verbosely written as Returns the vertex position at the given vertex index.

Not sure if it's better.

Nya

[mateuseap]

@fire, what are your thoughts on the new description? I aimed for brevity, but I'm open to adding more detail if you think it's necessary! Also, I liked your previous suggestion

[YuriSizov]

This is at least consistent with the rest of the description. That said, I'm not a huge fan of "the given vertex" when the user actually gives an index. But that can be a discussion for another day.

[akien-mga]

Thanks!