pub fn get_preferred_language_for_format(
state: &EiteState,
format: &str,
direction: &str,
) -> Result<String>Expand description
Preferred language (variant) for a format/direction. Defaults to
the environment language (state.env_language) and scans the variant
list for entries beginning with “lang_”.
Returns the variant label (e.g., “lang_en”) if found; otherwise the
environment language.
(Original: getPreferredLanguageForFormat)