Add an example for the variant generator and specify FQCNs used
Add an example for the variant generator and specify FQCNs used

- Provide an explicit example, with details of options and variants generated.
- Improve descriptions.
- Add use statement for `VariantGenerator` to code block.
- Define FQCN for `VariantGeneratorInterface`
Mozan/Sylius,polisys/Sylius,juramy/Sylius,itinance/Sylius,Joypricecorp/Sylius,itinance/Sylius,regnisolbap/Sylius,mkilmanas/Sylius,adamelso/Sylius,ReissClothing/Sylius,mbabker/Sylius,vihuvac/Sylius,ktzouno/Sylius,tuka217/Sylius,pamil/Sylius,pjedrzejewski/Sylius,Rvanlaak/Sylius,PyRowMan/Sylius,CoderMaggie/Sylius,venyii/Sylius,ravaj-group/Sylius,Sylius/Sylius,DorianCMore/Sylius,davalb/Sylius,okwinza/Sylius,TeamNovatek/Sylius,Niiko/Sylius,ezecosystem/Sylius,gorkalaucirica/Sylius,ylastapis/Sylius,psyray/Sylius,ezecosystem/Sylius,GSadee/Sylius,polisys/Sylius,TeamNovatek/Sylius,coudenysj/Sylius,patrick-mcdougle/Sylius,polisys/Sylius,Joypricecorp/Sylius,sweoggy/Sylius,tuka217/Sylius,gseidel/Sylius,Pitoune/Sylius,sweoggy/Sylius,sweoggy/Sylius,dragosprotung/Sylius,TeamNovatek/Sylius,torinaki/Sylius,psren/Sylius,gabiudrescu/Sylius,polisys/Sylius,ktzouno/Sylius,MichaelKubovic/Sylius,gabiudrescu/Sylius,ktzouno/Sylius,dragosprotung/Sylius,cdaguerre/Sylius,videni/Sylius,DorianCMore/Sylius,coudenysj/Sylius,cdaguerre/Sylius,fredcollet/Sylius,Brille24/Sylius,loic425/Sylius,SyliusBot/Sylius,DorianCMore/Sylius,Pitoune/Sylius,Brille24/Sylius,michalmarcinkowski/Sylius,foobarflies/Sylius,dragosprotung/Sylius,nakashu/Sylius,Pitoune/Sylius,ravaj-group/Sylius,tuka217/Sylius,juramy/Sylius,Ejobs/Sylius,fredcollet/Sylius,gruberro/Sylius,Brille24/Sylius,gorkalaucirica/Sylius,gseidel/Sylius,nakashu/Sylius,steffenbrem/Sylius,mheki/Sylius,psyray/Sylius,MichaelKubovic/Sylius,ylastapis/Sylius,diimpp/Sylius,mkilmanas/Sylius,axelvnk/Sylius,itinance/Sylius,lchrusciel/Sylius,mkilmanas/Sylius,gruberro/Sylius,kayue/Sylius,gseidel/Sylius,TheMadeleine/Sylius,pamil/Sylius,patrick-mcdougle/Sylius,GSadee/Sylius,lchrusciel/Sylius,torinaki/Sylius,bretto36/Sylius,gseidel/Sylius,coudenysj/Sylius,cdaguerre/Sylius,adamelso/Sylius,steffenbrem/Sylius,ReissClothing/Sylius,mbabker/Sylius,Arminek/Sylius,vihuvac/Sylius,ktzouno/Sylius,inssein/Sylius,Lowlo/Sylius,patrick-mcdougle/Sylius,ylastapis/Sylius,bretto36/Sylius,tuka217/Sylius,danut007ro/Sylius,patrick-mcdougle/Sylius,kayue/Sylius,ezecosystem/Sylius,Mozan/Sylius,Niiko/Sylius,michalmarcinkowski/Sylius,diimpp/Sylius,adamelso/Sylius,ylastapis/Sylius,rpg600/Sylius,davalb/Sylius,davalb/Sylius,videni/Sylius,Rvanlaak/Sylius,PyRowMan/Sylius,CoderMaggie/Sylius,itinance/Sylius,PyRowMan/Sylius,davalb/Sylius,inssein/Sylius,patrick-mcdougle/Sylius,ravaj-group/Sylius,bitbager/Sylius,101medialab/Sylius,regnisolbap/Sylius,gabiudrescu/Sylius,danut007ro/Sylius,NeverResponse/Sylius,Sylius/Sylius,SyliusBot/Sylius,videni/Sylius,lchrusciel/Sylius,psren/Sylius,pjedrzejewski/Sylius,Rvanlaak/Sylius,axelvnk/Sylius,jjanvier/Sylius,psren/Sylius,gmoigneu/platformsh-integrations,axelvnk/Sylius,mbabker/Sylius,venyii/Sylius,101medialab/Sylius,antonioperic/Sylius,Ejobs/Sylius,jvahldick/Sylius,inssein/Sylius,mheki/Sylius,Arminek/Sylius,gmoigneu/platformsh-integrations,cdaguerre/Sylius,fredcollet/Sylius,TheMadeleine/Sylius,nakashu/Sylius,danut007ro/Sylius,Joypricecorp/Sylius,bretto36/Sylius,101medialab/Sylius,ravaj-group/Sylius,adamelso/Sylius,coudenysj/Sylius,juramy/Sylius,Lowlo/Sylius,vihuvac/Sylius,gmoigneu/platformsh-integrations,CoderMaggie/Sylius,michalmarcinkowski/Sylius,torinaki/Sylius,ReissClothing/Sylius,psyray/Sylius,Zales0123/Sylius,bitbager/Sylius,Rvanlaak/Sylius,rpg600/Sylius,PyRowMan/Sylius,diimpp/Sylius,fredcollet/Sylius,Ejobs/Sylius,bretto36/Sylius,steffenbrem/Sylius,Mozan/Sylius,videni/Sylius,Ejobs/Sylius,cdaguerre/Sylius,axelvnk/Sylius,regnisolbap/Sylius,psyray/Sylius,ezecosystem/Sylius,jvahldick/Sylius,ReissClothing/Sylius,Zales0123/Sylius,davalb/Sylius,coudenysj/Sylius,gmoigneu/platformsh-integrations,NeverResponse/Sylius,Lowlo/Sylius,tuka217/Sylius,bitbager/Sylius,steffenbrem/Sylius,bitbager/Sylius,polisys/Sylius,psren/Sylius,adamelso/Sylius,GSadee/Sylius,NeverResponse/Sylius,gruberro/Sylius,Lowlo/Sylius,SyliusBot/Sylius,foobarflies/Sylius,mbabker/Sylius,TeamNovatek/Sylius,jjanvier/Sylius,TeamNovatek/Sylius,okwinza/Sylius,venyii/Sylius,Arminek/Sylius,rpg600/Sylius,NeverResponse/Sylius,Mozan/Sylius,gabiudrescu/Sylius,ReissClothing/Sylius,inssein/Sylius,TheMadeleine/Sylius,danut007ro/Sylius,jjanvier/Sylius,regnisolbap/Sylius,pjedrzejewski/Sylius,kayue/Sylius,steffenbrem/Sylius,DorianCMore/Sylius,Niiko/Sylius,okwinza/Sylius,TheMadeleine/Sylius,pjedrzejewski/Sylius,gorkalaucirica/Sylius,torinaki/Sylius,Pitoune/Sylius,loic425/Sylius,jvahldick/Sylius,CoderMaggie/Sylius,sweoggy/Sylius,michalmarcinkowski/Sylius,gorkalaucirica/Sylius,axelvnk/Sylius,MichaelKubovic/Sylius,dragosprotung/Sylius,rpg600/Sylius,juramy/Sylius,antonioperic/Sylius,Ejobs/Sylius,okwinza/Sylius,mheki/Sylius,Niiko/Sylius,jjanvier/Sylius,loic425/Sylius,gruberro/Sylius,okwinza/Sylius,vihuvac/Sylius,mkilmanas/Sylius,foobarflies/Sylius,psyray/Sylius,MichaelKubovic/Sylius,jvahldick/Sylius,venyii/Sylius,foobarflies/Sylius,Brille24/Sylius,Sylius/Sylius,Zales0123/Sylius,juramy/Sylius,mheki/Sylius,pamil/Sylius,ravaj-group/Sylius,antonioperic/Sylius,Mozan/Sylius,fredcoll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