GeocodeOptions.locale loses script and country codes

GeocodeOptions only passes along the bare language code to the Geocoding API. For example, even if the system locale is Traditional Chinese (Hong Kong) and the developer sets the locale property to Locale.current, the language query parameter ends up being zh instead of zh-Hant-HK. GeocodeOptions should pass along the entire locale identifier; it would be API’s responsibility to strip any components it doesn’t need or understand.

/cc @apendleton

从 MapboxGeocoder/MBGeocodeOptions.swift 第 101 行附近开始，这里 GeocodeOptions 将 locale 传递给 Geocoding API。跟踪 locale 如何成为 language query parameter，并验证像 zh-Hant-HK 这样的 locale 是否保持不变。只有传递完整的 locale identifier，而不只是其基本语言代码，才算完成。