"Create Benchmark" tutorial incorrect import

from Jeff Bowers:
> the very first snippet of code in the “Create Benchmark” section of the tutorial should not work as it requires us to import brainscore and from there brainscore.benchmarks etc. Looking at the repository, this seems to have changed to vision and brainscore_vision.benchmarks.

Find the tutorial's “Create Benchmark” section and inspect its first code snippet. Update the outdated brainscore import to the current vision and brainscore_vision.benchmarks imports, then verify that the snippet matches the repository's current package structure.

Written by the indexing model from the issue text.