Update shading_language.rst

[stuckupfool]

I'm proposing a small change to the shading language reference docs to make it clear that per-instance uniform arrays are not supported. Currently the docs mention that per-instance uniforms do not support textures and proceeds to give an example involving uniform texture arrays. However when I read the docs, it wasn't clear to me that non-texture uniform arrays (e.g: instance uniform vec3 my_arr[3]) are also not supported.

[Calinou]

Looks good to me.

cc @clayjohn (just to make sure this is correct, and an intended limitation rather than a bug)

[stuckupfool]

Thanks @Calinou.

For reference, the shader editor surfaces this error when using instance with a uniform array:

[Calinou]

For reference, the shader editor surfaces this error when using instance with a uniform array:

This makes sense, although we should probably change that error message to be more user-friendly (it kind of reads like an internal error right now).