Representation of a form field within a PDF document.
@type kind() :: :button | :text | :choice | :signature | :unknown
@type t() :: %PdfElixide.Form.Field{kind: kind(), name: String.t(), value: value()}
@type value() :: {:text, String.t()} | {:boolean, boolean()} | {:name, String.t()} | {:array, [String.t()]} | nil