cli.rb: rename "--installed-plugins" switch to "--plugins"
cli.rb: rename "--installed-plugins" switch to "--plugins"

It was always a PITA to type this.

ooohiroyukiooo/pry,josue804/debunker,geoffreylitt/pry,pvdb/pry,ooohiroyukiooo/pry,icebreaker/pry,bronzdoc/pry,caporta/pry,sideci-sample/sideci-sample-pry,jasnow/pry,ngpestelos/pry,shockone/pry,tdg5/pry,caporta/pry,raeno/pry,jasonm23/pry,gfvcastro/pry,sferik/pry,raeno/pry,deivid-rodriguez/pry,jasnow/pry,icebreaker/pry,pvdb/pry,nju520/pry,85x14/pry,shockone/pry,jasonm23/pry,scalixte-mdsol/pry,bronzdoc/pry,caporta/pry,geoffreylitt/pry,ooohiroyukiooo/pry,ngpestelos/pry,jasonm23/pry,sferik/pry,tdg5/pry,gfvcastro/pry,tdg5/pry,nju520/pry,raeno/pry,printercu/pry,josue804/debunker,scalixte-mdsol/pry,shockone/pry,nju520/pry,printercu/pry,85x14/pry,jasnow/pry,scalixte-mdsol/pry,85x14/pry