Expand on helpers available in Action Mailer
Expand on helpers available in Action Mailer

Remove 'now just' — document the current state in an accessible way. Make it clear the set of helpers isn't **exactly** the same

Add references to `mailer` and `message` helpers which can be very useful.

`attachments` is already covered in "Making Inline Attachments"

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