Add baseline defaults section [ci skip]
Add baseline defaults section [ci skip]

Mentioning the baseline default for a config option can be confusing
when that default is overridden by `config.load_defaults`.  To avoid
that confusion, this commit relocates such baseline defaults from their
explanatory paragraphs to a "Baseline defaults" section that flows with
the other `config.load_defaults` sections.

Ideally, when we override other baseline defaults in the future, we will
relocate mention of them as done here.

Closes #39387.

BlakeWilliams/rails,BlakeWilliams/rails,eileencodes/rails,rafaelfranca/omg-rails,esparta/rails,kmcphillips/rails,Edouard-chin/rails,yahonda/rails,tgxworld/rails,BlakeWilliams/rails,eileencodes/rails,yahonda/rails,rails/rails,Vasfed/rails,betesh/rails,Envek/rails,yalab/rails,repinel/rails,tjschuck/rails,yalab/rails,betesh/rails,joonyou/rails,repinel/rails,joonyou/rails,Stellenticket/rails,esparta/rails,tjschuck/rails,EmmaB/rails-1,repinel/rails,rails/rails,lcreid/rails,tgxworld/rails,MSP-Greg/rails,tjschuck/rails,Erol/rails,betesh/rails,tgxworld/rails,eileencodes/rails,MSP-Greg/rails,yawboakye/rails,rafaelfranca/omg-rails,Vasfed/rails,joonyou/rails,yahonda/rails,vipulnsward/rails,esparta/rails,Erol/rails,Edouard-chin/rails,yawboakye/rails,Envek/rails,rails/rails,Vasfed/rails,kmcphillips/rails,starknx/rails,kddeisz/rails,bogdanvlviv/rails,lcreid/rails,kddeisz/rails,joonyou/rails,Envek/rails,repinel/rails,eileencodes/rails,Envek/rails,bogdanvlviv/rails,schuetzm/rails,starknx/rails,bogdanvlviv/rails,MSP-Greg/rails,yalab/rails,yawboakye/rails,starknx/rails,vipulnsward/rails,esparta/rails,yawboakye/rails,lcreid/rails,Erol/rails,BlakeWilliams/rails,georgeclaghorn/rails,georgeclaghorn/rails,vipulnsward/rails,EmmaB/rails-1,kmcphillips/rails,rails/rails,Vasfed/rails,rafaelfranca/omg-rails,EmmaB/rails-1,vipulnsward/rails,tgxworld/rails,Edouard-chin/rails,yahonda/rails,Stellenticket/rails,kmcphillips/rails,georgeclaghorn/rails,betesh/rails,schuetzm/rails,kddeisz/rails,Stellenticket/rails,bogdanvlviv/rails,schuetzm/rails,kddeisz/rails,tjschuck/rails,yalab/rails,Erol/rails,Stellenticket/rails,georgeclaghorn/rails,Edouard-chin/rails,lcreid/rails,MSP-Greg/rails,schuetzm/rails