Auto merge of #14943 - nox:external-script-kind, r=jdm
Auto merge of #14943 - nox:external-script-kind, r=jdm

Introduce ExternalScriptKind to simplify HTMLScriptElement::prepare

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