Add index method to FormBuilder. Useful when you use field_for and need to know the index number into the iteration.

hash.

Closes #2492 and #5615

objectify_options method should be applied to the proper options arg.

See explanation and example of the bug - https://github.com/kryzhovnik/rails_field_error_proc_bug_example

Commit 56089ca9 introduced a backward
incompatible change by changing the method signature of the FormBuilder.
This brings back the same method signature warning in case someone gives
a block to the builder.

More info: https://github.com/rails/rails/commit/56089ca986c767763f29159c8de0aa1ebabfd4d2#commitcomment-1116166

Minor tweak to previous comments on form_for and form_helper.rb preamble

Fixes #5324 by removing default size options from input:text and default cols and rows options from textarea.

(endpoints are generated by form_for without reference to the form builder)

uses PATCH for the forms of persisted records, and routes PATCH and PUT to the update action of resources

PATCH is the correct HTML verb to map to the #update action. The
semantics for PATCH allows for partial updates, whereas PUT requires a
complete replacement.

Changes:
* adds config.default_method_for_update you can set to :patch
* optionally use PATCH instead of PUT in resource routes and forms
* adds the #patch verb to routes to detect PATCH requests
* adds #patch? to Request
* changes documentation and comments to indicate support for PATCH

This change maintains complete backwards compatibility by keeping :put
as the default for config.default_method_for_update.

* Do not reopen AV::Base to define default form builder
  Inside the load hook we are already in AV::Base context.

* Do not pass the given block to the form builder
  The block is evaluated in fields_for context using capture, with the
  builder as argument. This means we do not need to give the block to the
  FormBuilder itself.

ActionView::Helpers