Add Russian SuperGLUE
Added the missing label classes and their explanations (to the best of my understanding) Thanks a lot ! Once the last comment about the label names is addressed we can merge :)
Hi,

This adds the [Russian SuperGLUE](https://russiansuperglue.com/) dataset. For the most part I reused the code for the original SuperGLUE, although there are some relatively minor differences in the structure that I accounted for.