Disable paragraph linking in RDoc formatting
Uses RDoc 4.x's Markdown implementation as last resort

If you do not have another markdown library on your system and are on
Ruby 2.x or have RDoc 4.x+ installed, YARD will now attempt to use
the markdown implementation provided in RDoc. To force RDoc's
implementation, use --markdown-provider rdoc:

    $ yard -m markdown -M rdoc

Requires RDoc 4.x+