Fix guides: plug code typo (#3784)
Fix guides: plug code typo (#3784)


optikfluffel/phoenix,rafbgarcia/phoenix,optikfluffel/phoenix,phoenixframework/phoenix,eksperimental/phoenix,0x00evil/phoenix,nshafer/phoenix,optikfluffel/phoenix,rafbgarcia/phoenix,phoenixframework/phoenix,phoenixframework/phoenix,jwarwick/phoenix,michalmuskala/phoenix,0x00evil/phoenix,jwarwick/phoenix,rafbgarcia/phoenix,0x00evil/phoenix,nshafer/phoenix,nshafer/phoenix,michalmuskala/phoenix,eksperimental/phoenix