The three backtick way of marking code blocks in markdown, has an alternate: indented by four spaces. That should be supported too - and should be an option in recording mode, with playback mode just adapting to what it encounters. A method/function on the recorder could be indentCodeBlocks() whatever is idiomatic for the style of API you are building.
GET and POST may be in the markdown as emphasised like GET or POST (asterisk or underscore before & after the word in the markdown). This should be optional too via a recorder method like emphasizeHttpVerbs() (or similar). The Playback mode should just adapt to what it encounters, without an explicit method call.