Better docs for AV::RecordIdentifier
Better docs for AV::RecordIdentifier

This commit intends to clarify the scope of ActionView::RecordIdentifier
methods `dom_id` and `dom_class`.

Most of the current documentation comes from da257eb8 (7 years ago) when
the decoupling of ActionView, ActiveRecord and ActiveModel was not a concern.

Since then, steps have been taken to reach such decoupling, especially
8ca17926 which duplicated ActionController::ModelNaming into
ActionView::ModelNaming explaining that:

> These are just a simple helpers for decoupling Active Model, so it does not
> make sense to extract it to Active Support, but the point is to decouple also
> Action View and Action Pack

As of today, ActionView::RecordIdentifier only includes `dom_id` and `dom_class`
so it makes sense to explicitly document those two methods, and leaving the
details of helpers like `div_for` in the corresponding files.

Moreover, I think it's important to mention in the documentation that
ActionView::RecordIdentifier **does not strictly depend on the ActiveRecord API**: any class `Post` implementing `post.to_key` and `post.model_name.param_key` will work.

[ci skip]

rossta/rails,kddeisz/rails,vassilevsky/rails,kamipo/rails,mathieujobin/reduced-rails-for-travis,Erol/rails,schuetzm/rails,xlymian/rails,kmayer/rails,bogdanvlviv/rails,maicher/rails,joonyou/rails,yhirano55/rails,MichaelSp/rails,rails/rails,esparta/rails,kddeisz/rails,Stellenticket/rails,odedniv/rails,deraru/rails,schuetzm/rails,Sen-Zhang/rails,Envek/rails,ledestin/rails,odedniv/rails,gauravtiwari/rails,schuetzm/rails,mtsmfm/railstest,kamipo/rails,ngpestelos/rails,untidy-hair/rails,rbhitchcock/rails,illacceptanything/illacceptanything,fabianoleittes/rails,Edouard-chin/rails,aditya-kapoor/rails,marklocklear/rails,samphilipd/rails,georgeclaghorn/rails,palkan/rails,baerjam/rails,baerjam/rails,printercu/rails,kachick/rails,bolek/rails,eileencodes/rails,88rabbit/newRails,pvalena/rails,Erol/rails,elfassy/rails,fabianoleittes/rails,utilum/rails,coreyward/rails,88rabbit/newRails,kmcphillips/rails,amoody2108/TechForJustice,travisofthenorth/rails,esparta/rails,tijwelch/rails,yasslab/railsguides.jp,ledestin/rails,flanger001/rails,bradleypriest/rails,tgxworld/rails,riseshia/railsguides.kr,utilum/rails,yasslab/railsguides.jp,Erol/rails,shioyama/rails,rbhitchcock/rails,arjes/rails,mtsmfm/rails,rossta/rails,BlakeWilliams/rails,notapatch/rails,tgxworld/rails,illacceptanything/illacceptanything,kenta-s/rails,tgxworld/rails,riseshia/railsguides.kr,hanystudy/rails,jeremy/rails,palkan/rails,travisofthenorth/rails,Spin42/rails,bogdanvlviv/rails,alecspopa/rails,gfvcastro/rails,MSP-Greg/rails,notapatch/rails,mijoharas/rails,rossta/rails,ttanimichi/rails,tgxworld/rails,maicher/rails,mechanicles/rails,kaspth/rails,assain/rails,betesh/rails,georgeclaghorn/rails,yasslab/railsguides.jp,odedniv/rails,flanger001/rails,ttanimichi/rails,kachick/rails,Envek/rails,jeremy/rails,ledestin/rails,mohitnatoo/rails,rafaelfranca/omg-rails,gcourtemanche/rails,MichaelSp/rails,utilum/rails,prathamesh-sonpatki/rails,assain/rails,gavingmiller/rails,arjes/rails,yawboakye/rails,EmmaB/rails-1,sealocal/rails,illacceptanything/illacceptanything,Edouard-chin/rails,xlymian/rails,elfassy/rails,travisofthenorth/rails,bolek/rails,vipulnsward/rails,mijoharas/rails,marklocklear/rails,pschambacher/rails,samphilipd/rails,kenta-s/rails,prathamesh-sonpatki/rails,MSP-Greg/rails,sergey-alekseev/rails,georgeclaghorn/rails,repinel/rails,voray/rails,gavingmiller/rails,iainbeeston/rails,untidy-hair/rails,yahonda/rails,lcreid/rails,mohitnatoo/rails,Spin42/rails,illacceptanything/illacceptanything,gavingmiller/rails,stefanmb/rails,shioyama/rails,mechanicles/rails,MSP-Greg/rails,pvalena/rails,mohitnatoo/rails,Stellenticket/rails,yalab/rails,coreyward/rails,arunagw/rails,yahonda/rails,Envek/rails,Vasfed/rails,repinel/rails,rafaelfranca/omg-rails,rails/rails,yalab/rails,vassilevsky/rails,lucasmazza/rails,illacceptanything/illacceptanything,eileencodes/rails,voray/rails,joonyou/rails,maicher/rails,matrinox/rails,baerjam/rails,Spin42/rails,kddeisz/rails,kirs/rails-1,hanystudy/rails,deraru/rails,tjschuck/rails,printercu/rails,brchristian/rails,felipecvo/rails,esparta/rails,joonyou/rails,alecspopa/rails,jeremy/rails,tjschuck/rails,notapatch/rails,stefanmb/rails,Stellenticket/rails,Envek/rails,kaspth/rails,kmcphillips/rails,yhirano55/rails,rbhitchcock/rails,yhirano55/rails,mijoharas/rails,starknx/rails,repinel/rails,illacceptanything/illacceptanything,yalab/rails,BlakeWilliams/rails,vassilevsky/rails,kddeisz/rails,shioyama/rails,iainbeeston/rails,BlakeWilliams/rails,jeremy/rails,mtsmfm/railstest,deraru/rails,xlymian/rails,schuetzm/rails,sergey-alekseev/rails,flanger001/rails,voray/rails,prathamesh-sonpatki/rails,MSP-Greg/rails,repinel/rails,brchristian/rails,yhirano55/rails,prathamesh-sonpatki/rails,mathieujobin/reduced-rails-for-travis,betesh/rails,marklocklear/rails,yalab/rails,fabianoleittes/rails,pschambacher/rails,bogdanvlviv/rails,starknx/rails,gcourtemanche/rails,lcreid/rails,Vasfed/rails,printercu/rails,mechanicles/rails,georgeclaghorn/rails,eileencodes/rails,assain/rails,stefanmb/rails,yahonda/rails,MichaelSp/rails,ttanimichi/rails,Edouard-chin/rails,illacceptanything/illacceptanything,lcreid/rails,kmcphillips/rails,fabianoleittes/rails,Stellenticket/rails,aditya-kapoor/rails,esparta/rails,yawboakye/rails,vipulnsward/rails,EmmaB/rails-1,illacceptanything/illacceptanything,tijwelch/rails,richseviora/rails,kamipo/rails,arunagw/rails,illacceptanything/illacceptanything,baerjam/rails,elfassy/rails,betesh/rails,tjschuck/rails,tijwelch/rails,untidy-hair/rails,betesh/rails,illacceptanything/illacceptanything,Erol/rails,sealocal/rails,mtsmfm/rails,felipecvo/rails,koic/rails,amoody2108/TechForJustice,riseshia/railsguides.kr,illacceptanything/illacceptanything,iainbeeston/rails,coreyward/rails,ngpestelos/rails,rails/rails,Edouard-chin/rails,untidy-hair/rails,kachick/rails,kirs/rails-1,felipecvo/rails,kenta-s/rails,rails/rails,koic/rails,illacceptanything/illacceptanything,rafaelfranca/omg-rails,richseviora/rails,illacceptanything/illacceptanything,ngpestelos/rails,kirs/rails-1,arjes/rails,illacceptanything/illacceptanything,88rabbit/newRails,richseviora/rails,sergey-alekseev/rails,kaspth/rails,Sen-Zhang/rails,riseshia/railsguides.kr,EmmaB/rails-1,lucasmazza/rails,mtsmfm/rails,arunagw/rails,yawboakye/rails,assain/rails,gfvcastro/rails,vipulnsward/rails,iainbeeston/rails,aditya-kapoor/rails,mohitnatoo/rails,hanystudy/rails,mechanicles/rails,eileencodes/rails,aditya-kapoor/rails,starknx/rails,Sen-Zhang/rails,illacceptanything/illacceptanything,mtsmfm/railstest,yasslab/railsguides.jp,kmayer/rails,alecspopa/rails,pschambacher/rails,travisofthenorth/rails,bradleypriest/rails,shioyama/rails,brchristian/rails,gcourtemanche/rails,arunagw/rails,koic/rails,Vasfed/rails,matrinox/rails,gauravtiwari/rails,pvalena/rails,bogdanvlviv/rails,sealocal/rails,bolek/rails,vipulnsward/rails,utilum/rails,samphilipd/rails,amoody2108/TechForJustice,gauravtiwari/rails,bradleypriest/rails,palkan/rails,gfvcastro/rails,notapatch/rails,yawboakye/rails,matrinox/rails,Vasfed/rails,deraru/rails,lucasmazza/rails,joonyou/rails,palkan/rails,yahonda/rails,mathieujobin/reduced-rails-for-travis,pvalena/rails,kmayer/rails,kmcphillips/rails,tjschuck/rails,flanger001/rails,lcreid/rails,printercu/rails,BlakeWilliams/rails,gfvcastro/rails