docs: remove outdated path_format config option
docs: remove outdated path_format config option

The example config contained a configuration key that's been unsupported for
years! How embarrassing.

randybias/beets,shanemikel/beets,jmwatte/beets,ttsda/beets,Wen777/beets,bj-yinyan/beets,shamangeorge/beets,lengtche/beets,mathstuf/beets,parapente/beets,mathstuf/beets,Andypsamp/CODfinalJUNIT,lightwang1/beets,krig/beets,ibmibmibm/beets,asteven/beets,diego-plan9/beets,YetAnotherNerd/beets,Andypsamp/CODjunit,jcoady9/beets,artemutin/beets,ruippeixotog/beets,arabenjamin/beets,madmouser1/beets,gabrielaraujof/beets,sadatay/beets,bj-yinyan/beets,jmwatte/beets,randybias/beets,ruippeixotog/beets,beetbox/beets,ibmibmibm/beets,parapente/beets,swt30/beets,PierreRust/beets,randybias/beets,arabenjamin/beets,untitaker/beets,mosesfistos1/beetbox,imsparsh/beets,sampsyo/beets,jackwilsdon/beets,randybias/beets,jmwatte/beets,Andypsamp/CODjunit,moodboom/beets,kareemallen/beets,Kraymer/beets,Andypsamp/CODjunit,drm00/beets,shanemikel/beets,moodboom/beets,sadatay/beets,marcuskrahl/beets,ttsda/beets,Kraymer/beets,tima/beets,lightwang1/beets,moodboom/beets,Andypsamp/CODfinalJUNIT,asteven/beets,artemutin/beets,ruippeixotog/beets,YetAnotherNerd/beets,dfc/beets,sampsyo/beets,lightwang1/beets,imsparsh/beets,LordSputnik/beets,bj-yinyan/beets,MyTunesFreeMusic/privacy-policy,PierreRust/beets,swt30/beets,YetAnotherNerd/beets,Andypsamp/CODjunit,pkess/beets,multikatt/beets,xsteadfastx/beets,mried/beets,beetbox/beets,diego-plan9/beets,xsteadfastx/beets,sampsyo/beets,Andypsamp/CODfinalJUNIT,Dishwishy/beets,jackwilsdon/beets,mried/beets,SusannaMaria/beets,artemutin/beets,gabrielaraujof/beets,shamangeorge/beets,Freso/beets,PierreRust/beets,ttsda/beets,mosesfistos1/beetbox,artemutin/beets,shanemikel/beets,andremiller/beets,SusannaMaria/beets,shanemikel/beets,xsteadfastx/beets,Dishwishy/beets,untitaker/beets,pkess/beets,beetbox/beets,marcuskrahl/beets,mried/beets,Andypsamp/CODfinalJUNIT,m-urban/beets,untitaker/beets,jcoady9/beets,kelvinhammond/beets,kelvinhammond/beets,m-urban/beets,dfc/beets,kelvinhammond/beets,moodboom/beets,jackwilsdon/beets,MyTunesFreeMusic/privacy-policy,gabrielaraujof/beets,LordSputnik/beets,lengtche/beets,andremiller/beets,ibmibmibm/beets,ruippeixotog/beets,tima/beets,mosesfistos1/beetbox,dfc/beets,marcuskrahl/beets,kareemallen/beets,asteven/beets,YetAnotherNerd/beets,beetbox/beets,swt30/beets,andremiller/beets,ttsda/beets,parapente/beets,mathstuf/beets,swt30/beets,SusannaMaria/beets,pkess/beets,krig/beets,pkess/beets,Andypsamp/CODfinalJUNIT,m-urban/beets,PierreRust/beets,asteven/beets,Wen777/beets,drm00/beets,MyTunesFreeMusic/privacy-policy,shamangeorge/beets,jackwilsdon/beets,imsparsh/beets,tima/beets,bj-yinyan/beets,tima/beets,SusannaMaria/beets,Freso/beets,madmouser1/beets,Kraymer/beets,sampsyo/beets,multikatt/beets,madmouser1/beets,drm00/beets,shamangeorge/beets,multikatt/beets,arabenjamin/beets,ibmibmibm/beets,madmouser1/beets,m-urban/beets,xsteadfastx/beets,Dishwishy/beets,drm00/beets,sadatay/beets,Dishwishy/beets,arabenjamin/beets,kelvinhammond/beets,Freso/beets,imsparsh/beets,krig/beets,parapente/beets,Kraymer/beets,MyTunesFreeMusic/privacy-policy,kareemallen/beets,untitaker/beets,marcuskrahl/beets,sadatay/beets,jcoady9/beets,kareemallen/beets,mried/beets,diego-plan9/beets,multikatt/beets,LordSputnik/beets,Andypsamp/CODjunit,lengtche/beets,diego-plan9/beets,jmwatte/beets,lengtche/beets,gabrielaraujof/beets,mathstuf/beets,mosesfistos1/beetbox,dfc/beets,LordSputnik/beets,lightwang1/beets,Wen777/beets,jcoady9/beets,Freso/beets