Categories of processing warnings.
@type t() :: :image_extraction_failed | :encoding_fallback | :truncated_input | :malformed_html | :sanitization_applied | :depth_limit_exceeded
@spec depth_limit_exceeded() :: t()
@spec encoding_fallback() :: t()
@spec image_extraction_failed() :: t()
@spec malformed_html() :: t()
@spec sanitization_applied() :: t()
@spec truncated_input() :: t()