Function render 

pub async fn render(
    file: PathBuf,
    root_path: &Path,
    oembed_timeout_ms: u64,
    link_transform_config: LinkTransformConfig,
    server_mode: bool,
    transcode_enabled: bool,
    valid_tag_sources: HashSet<String>,
    review: ReviewLines,
    mark_incomplete: bool,
    incomplete_markers: &[String],
    wikilink_index: Option<Arc<WikilinkIndex>>,
) -> Result<MarkdownRenderResult, MarkdownError>