Remove testing views guide from mix.exs
Remove testing views guide from mix.exs

The testing views guide does not have any contents and should not be
included in the documentation.

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