[ruby/en] Make style fixes to conform to Ruby style guide

Made style fixes to conform to Ruby style guide.
Added a reference to a community-driven Ruby coding style guide.
I agree with @Nami-Doc in that it "seems both less readable and inconsistent" because I always make sure to have spaces around my operators. But, if the community-based Ruby style guide-lines says to not have spaces, then I agree to not have spaces. Even though it drives me crazy not to have spaces around operators, I can see why they omit them.