maint: miscellaneous style fixes for .m files * audio/mu2lin.m, deprecated/cut.m, general/cplxpair.m, general/genvarname.m, geometry/rectint.m, help/gen_doc_cache.m, image/hsv2rgb.m, image/rainbow.m, io/textscan.m, miscellaneous/bzip2.m, miscellaneous/compare_versions.m, miscellaneous/fact.m, miscellaneous/menu.m, optimization/fminbnd.m, optimization/fminunc.m, optimization/fzero.m, optimization/sqp.m, plot/__gnuplot_drawnow__.m, plot/axis.m, plot/findobj.m, plot/legend.m, plot/peaks.m, plot/private/__errplot__.m, plot/private/__fltk_print__.m, plot/private/__go_draw_axes__.m, plot/private/__patch__.m, polynomial/pchip.m, polynomial/residue.m, signal/periodogram.m, sparse/sprandsym.m, statistics/base/moment.m, statistics/distributions/expcdf.m, statistics/distributions/expinv.m, statistics/distributions/exppdf.m, statistics/tests/prop_test_2.m, statistics/tests/sign_test.m, statistics/tests/t_test.m, statistics/tests/t_test_2.m, statistics/tests/t_test_regression.m, strings/regexptranslate.m, time/datetick.m: Style fixes.

--- a/scripts/plot/__gnuplot_drawnow__.m
+++ b/scripts/plot/__gnuplot_drawnow__.m
@@ -259,9 +259,9 @@
         size_str = "";
       endif
     else
-      if isempty (h)
+      if (isempty (h))
         disp ("gnuplot_set_term: figure handle is empty");
-      elseif !isfigure(h)
+      elseif (! isfigure (h))
         disp ("gnuplot_set_term: not a figure handle");
       endif
       title_str = "";