blog: Some strange code block highlighting

[ee7]

https://nim-lang.org/blog/2021/02/03/this-month-with-nim.html#linerino

The line containing for (tut, _) in levels has weird extra background highlighting:

[narimiran]

I think this is on the Jekyll's side; it doesn't ignore _ inside of a code block when it should. I.e. not much we can do, except maybe rewrite this line as for (tut, x) in levels:?