Delete callbacks.rb

define_callback is from Sass and is not used in Haml.

yard/callbacks.rb

@@ -1,29 +0,0 @@
-class CallbacksHandler < YARD::Handlers::Ruby::Legacy::Base
-  handles(/\Adefine_callback(\s|\()/)
-
-  def process
-    callback_name = tokval(statement.tokens[2])
-    attr_index = statement.comments.each_with_index {|c, i| break i if c[0] == ?@}
-    if attr_index.is_a?(Fixnum)
-      docstring = statement.comments[0...attr_index]
-      attrs = statement.comments[attr_index..-1]
-    else
-      docstring = statement.comments
-      attrs = []
-    end
-
-    yieldparams = ""
-    attrs.reject! do |a|
-      next unless a =~ /^@yield *(\[.*?\])/
-      yieldparams = $1
-      true
-    end
-
-    o = register(MethodObject.new(namespace, "on_#{callback_name}", scope))
-    o.docstring = docstring + [
-      "@return [void]",
-      "@yield #{yieldparams} When the callback is run"
-    ] + attrs
-    o.signature = true
-  end
-end