Avoid using {...} for multi-line blocks in Rspec change block

[unforced]

In Rspec, a change block is required to use {...} instead of do...end. However, rubocop still warns about this.

[jonas054]

This is basically the same problem as in #373, but with an extra twist. Since these change blocks can look something like:

expect { Counter.increment }.to change {
  Counter.count
}.from(0).to(1)

There are two methods named to, something that my current solution in #378 can't handle. I'll take this case into consideration and make a better solution.