Auto merge of #19336 - servo:jdm-patch-6, r=emilio
Auto merge of #19336 - servo:jdm-patch-6, r=emilio

Instruct how to deal with outdated manifests.

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SimonSapin/servo,rnestler/servo,sadmansk/servo,szeged/servo,cbrewster/servo,DominoTree/servo,jimberlage/servo,canaltinova/servo,emilio/servo,SimonSapin/servo,saneyuki/servo,upsuper/servo,notriddle/servo,paulrouget/servo,ConnorGBrewster/servo,jimberlage/servo,szeged/servo,saneyuki/servo,avadacatavra/servo,paulrouget/servo,paulrouget/servo,SimonSapin/servo,sadmansk/servo,mattnenterprise/servo,fiji-flo/servo,DominoTree/servo,pyfisch/servo,peterjoel/servo,pyfisch/servo,KiChjang/servo,canaltinova/servo,KiChjang/servo,dsandeephegde/servo,upsuper/servo,mbrubeck/servo,saneyuki/servo,notriddle/servo,anthgur/servo,szeged/servo,jimberlage/servo,avadacatavra/servo,splav/servo,anthgur/servo,dati91/servo,dsandeephegde/servo,saneyuki/servo,thiagopnts/servo,mbrubeck/servo,larsbergstrom/servo,peterjoel/servo,szeged/servo,nnethercote/servo,cbrewster/servo,szeged/servo,saneyuki/servo,rnestler/servo,jimberlage/servo,splav/servo,CJ8664/servo,CJ8664/servo,pyfisch/servo,anthgur/servo,notriddle/servo,peterjoel/servo,thiagopnts/servo,DominoTree/servo,splav/servo,splav/servo,larsbergstrom/servo,KiChjang/servo,pyfisch/servo,jimberlage/servo,dati91/servo,paulrouget/servo,canaltinova/servo,dati91/servo,upsuper/servo,jimberlage/servo,DominoTree/servo,cbrewster/servo,sadmansk/servo,nnethercote/servo,upsuper/servo,cbrewster/servo,mbrubeck/servo,dati91/servo,splav/servo,anthgur/servo,sadmansk/servo,rnestler/servo,CJ8664/servo,paulrouget/servo,peterjoel/servo,dsandeephegde/servo,ConnorGBrewster/servo,anthgur/servo,paulrouget/servo,paulrouget/servo,paulrouget/servo,DominoTree/servo,KiChjang/servo,saneyuki/servo,mbrubeck/servo,notriddle/servo,nnethercote/servo,larsbergstrom/servo,rnestler/servo,upsuper/servo,splav/servo,splav/servo,mbrubeck/servo,dati91/servo,anthgur/servo,saneyuki/servo,larsbergstrom/servo,SimonSapin/servo,szeged/servo,jimberlage/servo,ConnorGBrewster/servo,CJ8664/servo,dsandeephegde/servo,nnethercote/servo,splav/servo,mattnenterprise/servo,larsbergstrom/servo,SimonSapin/servo,dsandeephegde/servo,larsbergstrom/servo,emilio/servo,mattnenterprise/servo,KiChjang/servo,CJ8664/servo,szeged/servo,sadmansk/servo,anthgur/servo,peterjoel/servo,dsandeephegde/servo,dsandeephegde/servo,emilio/servo,notriddle/servo,thiagopnts/servo,peterjoel/servo,rnestler/servo,anthgur/servo,fiji-flo/servo,avadacatavra/servo,szeged/servo,mbrubeck/servo,rnestler/servo,fiji-flo/servo,nnethercote/servo,pyfisch/servo,thiagopnts/servo,nnethercote/servo,splav/servo,canaltinova/servo,dati91/servo,avadacatavra/servo,mbrubeck/servo,canaltinova/servo,KiChjang/servo,upsuper/servo,pyfisch/servo,KiChjang/servo,pyfisch/servo,emilio/servo,dati91/servo,cbrewster/servo,szeged/servo,upsuper/servo,avadacatavra/servo,mbrubeck/servo,dsandeephegde/servo,larsbergstrom/servo,rnestler/servo,ConnorGBrewster/servo,mattnenterprise/servo,DominoTree/servo,fiji-flo/servo,avadacatavra/servo,emilio/servo,CJ8664/servo,emilio/servo,emilio/servo,cbrewster/servo,jimberlage/servo,pyfisch/servo,nnethercote/servo,SimonSapin/servo,saneyuki/servo,nnethercote/servo,SimonSapin/servo,ConnorGBrewster/servo,sadmansk/servo,thiagopnts/servo,notriddle/servo,notriddle/servo,pyfisch/servo,cbrewster/servo,DominoTree/servo,jimberlage/servo,paulrouget/servo,canaltinova/servo,paulrouget/servo,rnestler/servo,dati91/servo,DominoTree/servo,upsuper/servo,emilio/servo,ConnorGBrewster/servo,pyfisch/servo,peterjoel/servo,nnethercote/servo,saneyuki/servo,splav/servo,mattnenterprise/servo,thiagopnts/servo,peterjoel/servo,emilio/servo,thiagopnts/servo,mattnenterprise/servo,cbrewster/servo,larsbergstrom/servo,notriddle/servo,fiji-flo/servo,CJ8664/servo,fiji-flo/servo,DominoTree/servo,saneyuki/servo,KiChjang/servo,KiChjang/servo,ConnorGBrewster/servo,DominoTree/servo,notriddle/servo,emilio/servo,szeged/servo,thiagopnts/servo,CJ8664/servo,larsbergstrom/servo,ConnorGBrewster/servo,nnethercote/servo,avadacatavra/servo,larsbergstrom/servo,sadmansk/servo,mattnenterprise/servo,SimonSapin/servo,notriddle/servo,peterjoel/servo,mattnenterprise/servo,KiChjang/servo,peterjoel/servo,sadmansk/servo,canaltinova/servo,avadacatavra/servo,canaltinova/servo,fiji-flo/servo,fiji-flo/servo