Function subparse::get_subtitle_format_by_extension_err

pub fn get_subtitle_format_by_extension_err(
    extension: Option<&OsStr>
) -> Result<SubtitleFormat>

Returns the subtitle format by the file extension.

Works exactly like get_subtitle_format_by_extension, but instead of None a UnknownFileFormat will be returned (for simpler error handling).

Option is used to simplify handling with PathBuf::extension().