handle_rdoc_link

# File lib/rdoc/markup/to_markdown.rb, line 148
  def handle_rdoc_link url
    case url
    when /^rdoc-ref:/ then
      $'
    when /^rdoc-label:footmark-(\d+)/ then
      "[^#{$1}]:"
    when /^rdoc-label:foottext-(\d+)/ then
      "[^#{$1}]"
    when /^rdoc-label:label-/ then
      gen_url url, $'
    when /^rdoc-image:/ then
      "![](#{$'})"
    when /^rdoc-[a-z]+:/ then
      $'
    end
  end