haml - support more colors when highlighting

[onebree]

Originally posted in: github-linguist/linguist#2814

Related issue: #3

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There are issues when rendering multi-line comments with -# and Ruby string interpolation. But in Vim, none of these issues appear. I don't know if this is because Vim uses a different highlighting template (which is probably does). But either way, I think more colors (not necessarily the same as my theme) will help.

I have no issue writing in HAML in Vim with railscast theme.

However, the highlighting provided by linguist is not nearly as expressive. (See screenshot if this issue has been closed.)

-#
  multi-line comment
  must be indented further than: -#

= bootstrap_form_for @address, as: :address, url: url do |f|
  %h2 General Information
  .panel.panel-default
    .panel-body
       %ul
         %li= "Company name: #{f.object.company.name}"
         %li= "Address type: #{f.object.type}"

  %h2 Address Details
  .panel.panel-default
    .panel-body
      .row
        .col-xs-12
          = f.text_field :address1
          = f.text_field :address2
      .row
        .col-xs-5
          = f.text_field :city
        .col-xs-4
          = f.collection_select :state_id, State.all.to_a, :id, :name
        .col-xs-3
          = f.text_field :zip

  .text-center= f.submit 'Submit', class: 'btn btn-success'