maint: Clean up m-files to follow Octave coding conventions. Try to trim long lines to < 80 chars. Use '##' for single line comments. Use '(...)' around tests for if/elseif/switch/while. Abut cell indexing operator '{' next to variable. Abut array indexing operator '(' next to variable. Use space between negation operator '!' and following expression. Use two newlines between endfunction and start of %!test or %!demo code. Remove unnecessary parens grouping between short-circuit operators. Remove stray extra spaces (typos) between variables and assignment operators. Remove stray extra spaces from ends of lines.

--- a/scripts/statistics/base/gls.m
+++ b/scripts/statistics/base/gls.m
@@ -82,7 +82,7 @@
   if (rx != ry)
     error ("gls: number of rows of X and Y must be equal");
   endif
-  if (!issquare (o) || ro != ry*cy)
+  if (! issquare (o) || ro != ry*cy)
     error ("gls: matrix O must be square matrix with rows = rows (Y) * cols (Y)");
   endif
 
@@ -129,7 +129,7 @@
 %! o = diag (ones (5,1));
 %! assert (gls (y,x,o), [3; 2], 50*eps);
 
-%% Test input validation
+## Test input validation
 %!error gls ()
 %!error gls (1)
 %!error gls (1, 2)