Check for spaces before comments

[agrimm]

Rubocop doesn't check that there's a space before comments.

The following passes Rubocop, even though there isn't a space between 1 and #:

def foo
  a = 1
  a += 1# Increment a by one
  a * 2
end

The Ruby style guide doesn't explicitly discourage such a style, but the examples it has involve having a space before the # character.

[bbatsov]

@agrimm 👍 Such a check definitely makes sense. @jonas054 Please, implement it when you can.

[bbatsov]

@agrimm Btw - feel free to mention this in the style guide.