Function upsert_fts_document 

pub fn upsert_fts_document(
    connection: &Connection,
    index_name: &str,
    tokenizer_mode: TokenizerMode,
    id: &str,
    file_path: &str,
    title: &str,
    content: &str,
) -> Result<FtsMutationResult>

写入或更新 FTS 文档（中英双语）。 Insert or update an FTS document (bilingual).