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/range.m
+++ b/scripts/statistics/base/range.m
@@ -56,7 +56,7 @@
 %!assert (range (magic (3), 2), [7; 4; 7])
 %!assert (range (2), 0)
 
-%% Test input validation
+## Test input validation
 %!error range ()
 %!error range (1, 2, 3)