Add support for hidden inputs (#6456)

Removed in 712ad7e,
but it is useful not having to write `@field[:name].value` etc. and AI
also makes mistakes there.

Author: SteffenDE

installer/templates/phx_web/components/core_components.ex

@@ -151,7 +151,7 @@ defmodule <%= @web_namespace %>.CoreComponents do
   attr :type, :string,
     default: "text",
     values: ~w(checkbox color date datetime-local email file month number password
-               search select tel text textarea time url week)
+               search select tel text textarea time url week hidden)
 
   attr :field, Phoenix.HTML.FormField,
     doc: "a form field struct retrieved from the form, for example: @form[:email]"
@@ -179,6 +179,12 @@ defmodule <%= @web_namespace %>.CoreComponents do
     |> input()
   end
 
+  def input(%{type: "hidden"} = assigns) do
+    ~H"""
+    <input type="hidden" id={@id} name={@name} value={@value} {@rest} />
+    """
+  end
+
   def input(%{type: "checkbox"} = assigns) do
     assigns =
       assign_new(assigns, :checked, fn ->