Invalid warning and correction by LineEndConcatenation

[agrimm]

Given the following code

def foo
  'Hello ' + # OPTIMIZE: Turn this into a constant.
  'world'
end

LineEndConcatenation will advocate using a \ instead of a +, and will automatically correct it given the autocorrect option, but this produces invalid Ruby

$ bundle exec rubocop -a line_end_concatenation.rb 
Inspecting 1 file
E

Offences:

line_end_concatenation.rb:2:12: C: [Corrected] Use \ instead of + to concatenate those strings.
  'Hello ' + # OPTIMIZE: Turn this into a constant.
           ^
line_end_concatenation.rb:2:12: E: bare backslash only allowed before newline
  'Hello ' \ # OPTIMIZE: Turn this into a constant.
           ^

1 file inspected, 2 offences detected, 1 offence corrected

[bbatsov]

Ops. I didn't take this into account. I'll have it fixed.