Fix indentation of statement keywords on dot call

[tonini]

This fixes the issue where statement keywords like for, if, else etc are used in a dot call syntax like the following:

defmodule Whois do
  def lookup1(domain) do
    case Server.for(domain) do <-
      {:ok, server} -> server
      :error -> {:error, :unsupported}
    end
  end
end

fixes #323