badfiles: Update doc about checker commands
badfiles: Update doc about checker commands

pkess/beets,shamangeorge/beets,marcuskrahl/beets,YetAnotherNerd/beets,shamangeorge/beets,m-urban/beets,mried/beets,xsteadfastx/beets,xsteadfastx/beets,sampsyo/beets,LordSputnik/beets,MyTunesFreeMusic/privacy-policy,gabrielaraujof/beets,kareemallen/beets,kelvinhammond/beets,pkess/beets,Dishwishy/beets,tima/beets,mosesfistos1/beetbox,swt30/beets,LordSputnik/beets,SusannaMaria/beets,sampsyo/beets,YetAnotherNerd/beets,tima/beets,Kraymer/beets,artemutin/beets,m-urban/beets,parapente/beets,sadatay/beets,m-urban/beets,Kraymer/beets,swt30/beets,sampsyo/beets,kelvinhammond/beets,randybias/beets,diego-plan9/beets,shamangeorge/beets,madmouser1/beets,asteven/beets,Dishwishy/beets,SusannaMaria/beets,sampsyo/beets,randybias/beets,jcoady9/beets,Freso/beets,pkess/beets,artemutin/beets,jmwatte/beets,gabrielaraujof/beets,jcoady9/beets,sadatay/beets,asteven/beets,marcuskrahl/beets,drm00/beets,jackwilsdon/beets,asteven/beets,sadatay/beets,Kraymer/beets,lightwang1/beets,mosesfistos1/beetbox,lengtche/beets,swt30/beets,MyTunesFreeMusic/privacy-policy,jmwatte/beets,tima/beets,shamangeorge/beets,MyTunesFreeMusic/privacy-policy,randybias/beets,lengtche/beets,xsteadfastx/beets,lengtche/beets,diego-plan9/beets,kelvinhammond/beets,parapente/beets,tima/beets,Kraymer/beets,drm00/beets,YetAnotherNerd/beets,ibmibmibm/beets,jackwilsdon/beets,ibmibmibm/beets,gabrielaraujof/beets,kareemallen/beets,Freso/beets,madmouser1/beets,mosesfistos1/beetbox,randybias/beets,Freso/beets,xsteadfastx/beets,artemutin/beets,diego-plan9/beets,YetAnotherNerd/beets,jackwilsdon/beets,sadatay/beets,kareemallen/beets,kareemallen/beets,marcuskrahl/beets,jackwilsdon/beets,mried/beets,pkess/beets,Freso/beets,SusannaMaria/beets,mosesfistos1/beetbox,asteven/beets,beetbox/beets,parapente/beets,beetbox/beets,MyTunesFreeMusic/privacy-policy,madmouser1/beets,lightwang1/beets,jmwatte/beets,drm00/beets,kelvinhammond/beets,LordSputnik/beets,marcuskrahl/beets,lightwang1/beets,jmwatte/beets,gabrielaraujof/beets,swt30/beets,lightwang1/beets,diego-plan9/beets,beetbox/beets,Dishwishy/beets,ibmibmibm/beets,ibmibmibm/beets,mried/beets,jcoady9/beets,jcoady9/beets,artemutin/beets,SusannaMaria/beets,lengtche/beets,LordSputnik/beets,Dishwishy/beets,mried/beets,drm00/beets,parapente/beets,m-urban/beets,beetbox/beets,madmouser1/beets