Function buscar_documentacao 

pub async fn buscar_documentacao(
    cliente: &Client,
    chave: &str,
    library_id: &str,
    query: Option<&str>,
    texto_plano: bool,
) -> Result<RespostaDocumentacao, ErroContext7>

Fetches documentation for library_id with an optional query filter.

texto_plano = true requests the txt content type instead of JSON. Returns Err(ErroContext7) on HTTP errors to enable retry in executar_com_retry.