Feature Request: Add Support to Customize Input Mappings

[klondikemarlen]

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Environment

• Ruby 3.1.2
• Rails 7.0.4
• Simple Form 5.1.0

Current behavior

If I want to customize the search input, e.g. f.input(:search, as: :search), I can't do so in a comfortable way.
I can do f.input(:search, as: :custom_search) and build a CustomSearchInput < SimpleForm::Inputs::StringInput, but this doesn't feel very natural.
I can also do SimpleForm::FormBuilder.mappings[:search] = CustomSearchInput, but this doesn't use a public interface.

Expected behavior

To be able to tweak the default SimpleForm::FormBuilder.mappings[:search] via a config option.
e.g.

# config/initializers/simple_form.rb
SimpleForm.setup do |config|
  config.form_builder_input_mappings = {
    search: CustomSearchInput,
  }
end