Slim Lexer: Fix multiline ruby code

[reneklacan]

This change fixes lexing of multiline string using \ at the end of the line.

Example:

= render( \
    partial: 'foo',
    locals: { \
      foo: :bar,
    },
  )

[reneklacan]

Looks like Travis CI failure is not related to my change.

[pyrmont]

@reneklacan Would you be able to add an example to the visual sample for Slim? That'll kick off a new build on Travis now that we've got that fixed.

[reneklacan]

Hi @pyrmont, thank you for merging my commit.

Would you be able to add an example to the visual sample for Slim?

Sorry, I'm not quite sure what do you mean by the visual sample for Slim? Can you point me to a specific file? I looked around for samples but didn't find anything.

[reneklacan]

I messed up a little bit while rebasing which automatically closed this PR so I opened a new one #1130