[ci skip] Fix documented version for `multiple_file_field_include_hidden`

[schmijos]

Rails 6.0 upgrade mentioned that behaviour will change in 7.1 (see https://guides.rubyonrails.org/upgrading_ruby_on_rails.html#active-storage-assignment-behavior-change). But it at least formally did not, see https://guides.rubyonrails.org/7_1_release_notes.html#active-storage-removals

[schmijos]

Ok. Now I am totally confused. Replace started to be default already with 6.0 https://guides.rubyonrails.org/v7.0/configuring.html#config-active-storage-replace-on-assign-to-many

[schmijos]

And I'm even a bit more confused because https://guides.rubyonrails.org/v6.0/configuring.html#config-active-storage-replace-on-assign-to-many doesn't exist.

[p8]

Hi @schmijos , maybe the original PR makes more sense? https://github.com/rails/rails/pull/46358

[skipkayhil]

And I'm even a bit more confused because https://guides.rubyonrails.org/v6.0/configuring.html#config-active-storage-replace-on-assign-to-many doesn't exist.

The direct linking unfortunately wasn't added until later, but the configuration is second to last in the Active Storage section

But it at least formally did not, see https://guides.rubyonrails.org/7_1_release_notes.html#active-storage-removals

I think this note in the link describes the change you are referring to:

Remove deprecated behavior when assigning to a collection of attachments. Instead of appending to the collection, the collection is now replaced.

So the timeline of changes is:

• new config replace_on_assign_to_many added in 6.0 and set to true with load_defaults 6.0 (https://github.com/rails/rails/commit/400b2103540e1dfb370eab29a891687d778ad357)
• the configuration was deprecated in 7.0 (https://github.com/rails/rails/commit/61a8cd6c8f9ce864ec9ada95239bfd85f1873f31)
• the configuration was removed in 7.1 (https://github.com/rails/rails/commit/c720b7eba8bab1d227553ad4f962bf35abd41c88) so now it always replaces

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For this PR, my suggestion would be to not mention the version at all. Rails 7.1, 7.2 and main all have the same behavior, which is to replace.