[RF-DOCS] Action View Form Helpers Guide [ci-skip]

[bhumi1102]

Motivation / Background

This Pull Request is for updating and improving the Action View Form Helpers Rails Guide documentation.

Details

In addition to updating the code examples and editing text for clarity and flow, here some more details on some of the changes:

• Do we still need an HTML5 warning at the end of the 1st section? It's pretty standard these days.
  --> agree, removed.
• Not sure the output of _form_with model: @article_ is 100% correct, might need to double check that.
  --> yes. updated this example and got the HTML output from my "guides playground" rails app.
• When we mention record.persisted? in record identification, could be a good plug to link to the Active Model guide on that.
  --> Hm...there is no direction mention, other than this https://guides.rubyonrails.org/active_model_basics.html#conversion
• Similar to STI, link to the guide / reference on it.
• Time Zone and Country Select should likely be broken into separate sub-sections (I don't mind still mentioning country select)
• Would the file upload example would be better with a CSV for local processing, rather than showing saving to local disk? (which is probably a very uncommon usage?)
• The labeled_form_with example could likely be simplified with _**options_ being all that it takes, instead of explicitly showing all possible kwargs.
• It may be better to show "complex forms" (section 10) right after the parameters (section 8), moving "forms to external resources" down... just because complex forms require exactly the fields_for incantation that was detailed further under the parameters section, so it seems a better continuation. (or potentially even reversed? complex forms then params? not sure)
• Under "complex forms", adding fields on the flow could be slightly expanded, it feels very "go figure".
  --> Yeah, not sure what to do about this one. Was thinking about removing it as there is not built-in support to showcase.

Testing

• Run guides:generate
• Run guides:lint
• Run rubocop on code samples

[superchilled]

Great job on this PR @bhumi1102 👍🏾

I made some suggestions in a few places. Hope it helps! 😃

[p8]

I think this whole section should use addresses instead of address for the form/parameters.
The association on person would probably be addresses as well and other examples above use addresses as well (this suggestion doesn't include all occurences as that was a bit diffuclt to do in Github 😞 )

Suggested change

	`person[address][#{address.id}][city]` instead of `person[address][city]`. This
	`person[addresses][#{address.id}][city]` instead of `person[addresses][city]`. This

Hmm, the next section implements this very similar example with nested attributes. Maybe this section should use a single address for a person instead?

[bhumi1102]

Hi @p8 - let me know if I misunderstood something but I double checked and it is indeed address as it is coming from within the loop @person.addresses.each do |address|:

  <% @person.addresses.each do |address| %>
    <%= person_form.fields_for address, index: address.id do |address_form| %>
      <%= address_form.text_field :city %>
    <% end %>
  <% end %>

The id specified using the index: option is what will then distinguish the addresses with person[address][23][city], I think that's the "feature" this section is trying to illustrate. Let me know if that make sense, or if I've misunderstood what you're getting at, happy to look into it more.

[p8]

This fields_for currently isn't linked:

Suggested change

	Let's say you want to render a form with a set of fields for each of a person's
	addresses. The [`fields_for`][] helper with its `:index` option can assist:
	Let's say you want to render a form with a set of fields for each of a person's
	addresses. The [`fields_for`][] helper with its `:index` option can assist:
	[`fields_for`]: https://api.rubyonrails.org/classes/ActionView/Helpers/FormBuilder.html#method-i-fields_for