simplifies Zeitwerk compat instructions in upgrading guide [skip ci]
simplifies Zeitwerk compat instructions in upgrading guide [skip ci]

repinel/rails,schuetzm/rails,MSP-Greg/rails,esparta/rails,eileencodes/rails,mechanicles/rails,rafaelfranca/omg-rails,yawboakye/rails,vipulnsward/rails,eileencodes/rails,iainbeeston/rails,BlakeWilliams/rails,prathamesh-sonpatki/rails,lcreid/rails,bogdanvlviv/rails,kmcphillips/rails,jeremy/rails,joonyou/rails,gauravtiwari/rails,fabianoleittes/rails,jeremy/rails,iainbeeston/rails,georgeclaghorn/rails,bogdanvlviv/rails,Stellenticket/rails,lcreid/rails,fabianoleittes/rails,arunagw/rails,iainbeeston/rails,jeremy/rails,notapatch/rails,EmmaB/rails-1,tjschuck/rails,joonyou/rails,lcreid/rails,yawboakye/rails,rails/rails,repinel/rails,starknx/rails,betesh/rails,eileencodes/rails,kddeisz/rails,Vasfed/rails,palkan/rails,mechanicles/rails,Edouard-chin/rails,lcreid/rails,BlakeWilliams/rails,prathamesh-sonpatki/rails,tgxworld/rails,yahonda/rails,MSP-Greg/rails,tjschuck/rails,esparta/rails,bogdanvlviv/rails,georgeclaghorn/rails,gauravtiwari/rails,yhirano55/rails,yahonda/rails,yalab/rails,BlakeWilliams/rails,jeremy/rails,prathamesh-sonpatki/rails,notapatch/rails,BlakeWilliams/rails,vipulnsward/rails,shioyama/rails,prathamesh-sonpatki/rails,eileencodes/rails,betesh/rails,arunagw/rails,yhirano55/rails,rafaelfranca/omg-rails,yalab/rails,mechanicles/rails,joonyou/rails,starknx/rails,EmmaB/rails-1,fabianoleittes/rails,Envek/rails,Envek/rails,Stellenticket/rails,schuetzm/rails,Vasfed/rails,yahonda/rails,yhirano55/rails,Erol/rails,Edouard-chin/rails,iainbeeston/rails,rails/rails,bogdanvlviv/rails,betesh/rails,yawboakye/rails,arunagw/rails,arunagw/rails,Vasfed/rails,esparta/rails,schuetzm/rails,MSP-Greg/rails,kddeisz/rails,esparta/rails,vipulnsward/rails,georgeclaghorn/rails,kmcphillips/rails,yalab/rails,starknx/rails,shioyama/rails,fabianoleittes/rails,Edouard-chin/rails,kddeisz/rails,shioyama/rails,rails/rails,tgxworld/rails,notapatch/rails,Envek/rails,yalab/rails,kmcphillips/rails,MSP-Greg/rails,tjschuck/rails,rafaelfranca/omg-rails,vipulnsward/rails,Erol/rails,notapatch/rails,betesh/rails,schuetzm/rails,repinel/rails,rails/rails,gauravtiwari/rails,Erol/rails,Erol/rails,georgeclaghorn/rails,yhirano55/rails,palkan/rails,mechanicles/rails,EmmaB/rails-1,kddeisz/rails,joonyou/rails,tgxworld/rails,Edouard-chin/rails,Stellenticket/rails,Vasfed/rails,Envek/rails,palkan/rails,yahonda/rails,repinel/rails,kmcphillips/rails,Stellenticket/rails,yawboakye/rails,palkan/rails,tjschuck/rails,tgxworld/rails,shioyama/rails