doc: Update more docstrings to have one sentence summary as first line. Reviewed statistics/ and @ftp/ in scripts directory. * scripts/@ftp/ascii.m, scripts/@ftp/binary.m, scripts/@ftp/cd.m, scripts/@ftp/dir.m, scripts/@ftp/ftp.m, scripts/@ftp/mget.m, scripts/@ftp/mput.m, scripts/statistics/base/center.m, scripts/statistics/base/cloglog.m, scripts/statistics/base/cov.m, scripts/statistics/base/gls.m, scripts/statistics/base/histc.m, scripts/statistics/base/iqr.m, scripts/statistics/base/kendall.m, scripts/statistics/base/kurtosis.m, scripts/statistics/base/logit.m, scripts/statistics/base/lscov.m, scripts/statistics/base/mahalanobis.m, scripts/statistics/base/mean.m, scripts/statistics/base/meansq.m, scripts/statistics/base/median.m, scripts/statistics/base/mode.m, scripts/statistics/base/moment.m, scripts/statistics/base/ols.m, scripts/statistics/base/ppplot.m, scripts/statistics/base/prctile.m, scripts/statistics/base/probit.m, scripts/statistics/base/range.m, scripts/statistics/base/ranks.m, scripts/statistics/base/run_count.m, scripts/statistics/base/runlength.m, scripts/statistics/base/skewness.m, scripts/statistics/base/spearman.m, scripts/statistics/base/statistics.m, scripts/statistics/base/std.m, scripts/statistics/base/table.m, scripts/statistics/base/var.m, scripts/statistics/base/zscore.m, scripts/statistics/distributions/betainv.m, scripts/statistics/distributions/binoinv.m, scripts/statistics/distributions/binopdf.m, scripts/statistics/distributions/cauchy_cdf.m, scripts/statistics/distributions/cauchy_inv.m, scripts/statistics/distributions/cauchy_pdf.m, scripts/statistics/distributions/chi2cdf.m, scripts/statistics/distributions/chi2inv.m, scripts/statistics/distributions/chi2pdf.m, scripts/statistics/distributions/discrete_cdf.m, scripts/statistics/distributions/discrete_inv.m, scripts/statistics/distributions/discrete_pdf.m, scripts/statistics/distributions/empirical_cdf.m, scripts/statistics/distributions/empirical_inv.m, scripts/statistics/distributions/empirical_pdf.m, scripts/statistics/distributions/expcdf.m, scripts/statistics/distributions/expinv.m, scripts/statistics/distributions/exppdf.m, scripts/statistics/distributions/finv.m, scripts/statistics/distributions/fpdf.m, scripts/statistics/distributions/gamcdf.m, scripts/statistics/distributions/gaminv.m, scripts/statistics/distributions/gampdf.m, scripts/statistics/distributions/geoinv.m, scripts/statistics/distributions/geopdf.m, scripts/statistics/distributions/hygecdf.m, scripts/statistics/distributions/hygeinv.m, scripts/statistics/distributions/hygepdf.m, scripts/statistics/distributions/kolmogorov_smirnov_cdf.m, scripts/statistics/distributions/laplace_cdf.m, scripts/statistics/distributions/laplace_inv.m, scripts/statistics/distributions/laplace_pdf.m, scripts/statistics/distributions/logistic_inv.m, scripts/statistics/distributions/logncdf.m, scripts/statistics/distributions/logninv.m, scripts/statistics/distributions/lognpdf.m, scripts/statistics/distributions/nbincdf.m, scripts/statistics/distributions/nbininv.m, scripts/statistics/distributions/nbinpdf.m, scripts/statistics/distributions/nbinrnd.m, scripts/statistics/distributions/normcdf.m, scripts/statistics/distributions/norminv.m, scripts/statistics/distributions/normpdf.m, scripts/statistics/distributions/poisscdf.m, scripts/statistics/distributions/poissinv.m, scripts/statistics/distributions/poisspdf.m, scripts/statistics/distributions/stdnormal_cdf.m, scripts/statistics/distributions/stdnormal_pdf.m, scripts/statistics/distributions/tcdf.m, scripts/statistics/distributions/tinv.m, scripts/statistics/distributions/tpdf.m, scripts/statistics/distributions/unidcdf.m, scripts/statistics/distributions/unidinv.m, scripts/statistics/distributions/unidpdf.m, scripts/statistics/distributions/unidrnd.m, scripts/statistics/distributions/unifcdf.m, scripts/statistics/distributions/unifinv.m, scripts/statistics/distributions/wblcdf.m, scripts/statistics/distributions/wblinv.m, scripts/statistics/distributions/wblpdf.m, scripts/statistics/distributions/wienrnd.m, scripts/statistics/models/private/logistic_regression_derivatives.m, scripts/statistics/models/private/logistic_regression_likelihood.m, scripts/statistics/tests/anova.m, scripts/statistics/tests/chisquare_test_homogeneity.m, scripts/statistics/tests/chisquare_test_independence.m, scripts/statistics/tests/cor_test.m, scripts/statistics/tests/f_test_regression.m, scripts/statistics/tests/hotelling_test.m, scripts/statistics/tests/kolmogorov_smirnov_test.m, scripts/statistics/tests/kolmogorov_smirnov_test_2.m, scripts/statistics/tests/kruskal_wallis_test.m, scripts/statistics/tests/manova.m, scripts/statistics/tests/mcnemar_test.m, scripts/statistics/tests/prop_test_2.m, scripts/statistics/tests/run_test.m, scripts/statistics/tests/sign_test.m, scripts/statistics/tests/t_test.m, scripts/statistics/tests/t_test_2.m, scripts/statistics/tests/t_test_regression.m, scripts/statistics/tests/u_test.m, scripts/statistics/tests/var_test.m, scripts/statistics/tests/welch_test.m, scripts/statistics/tests/wilcoxon_test.m, scripts/statistics/tests/z_test.m, scripts/statistics/tests/z_test_2.m: Update more docstrings to have one sentence summary as first line.

--- a/scripts/statistics/base/gls.m
+++ b/scripts/statistics/base/gls.m
@@ -18,7 +18,9 @@
 
 ## -*- texinfo -*-
 ## @deftypefn {Function File} {[@var{beta}, @var{v}, @var{r}] =} gls (@var{y}, @var{x}, @var{o})
-## Generalized least squares estimation for the multivariate model
+## Generalized least squares model.
+##
+## Perform a generalized least squares estimation for the multivariate model
 ## @tex
 ## $y = x b + e$
 ## with $\bar{e} = 0$ and cov(vec($e$)) = $(s^2)o$,