Delete typo in plug guide (#2642)
Delete typo in plug guide (#2642)

This line looks like typo and it has two bugs anyway.

1. the comma shouldn't be there
2. if it's a function plug, the first argument should be `` conn `` instead of `` id ``

So I guess it's a typo. Feel free to close it if it's not a typo. Or let me know how to fix that line so I can help fix it.

Thanks!
mitchellhenke/phoenix,stevedomin/phoenix,Joe-noh/phoenix,nshafer/phoenix,mobileoverlord/phoenix,eksperimental/phoenix,gjaldon/phoenix,phoenixframework/phoenix,Gazler/phoenix,0x00evil/phoenix,pap/phoenix,Joe-noh/phoenix,evax/phoenix,Gazler/phoenix,mschae/phoenix,optikfluffel/phoenix,0x00evil/phoenix,keathley/phoenix,0x00evil/phoenix,rafbgarcia/phoenix,nshafer/phoenix,dmarkow/phoenix,dmarkow/phoenix,gjaldon/phoenix,optikfluffel/phoenix,pap/phoenix,stevedomin/phoenix,michalmuskala/phoenix,optikfluffel/phoenix,mitchellhenke/phoenix,michalmuskala/phoenix,phoenixframework/phoenix,Kosmas/phoenix,keathley/phoenix,Kosmas/phoenix,rafbgarcia/phoenix,jwarwick/phoenix,nshafer/phoenix,phoenixframework/phoenix,jwarwick/phoenix,eksperimental/phoenix,mobileoverlord/phoenix,rafbgarcia/phoenix,evax/phoenix,mschae/phoenix