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/miscellaneous/genvarname.m
+++ b/scripts/miscellaneous/genvarname.m
@@ -210,7 +210,7 @@
 ## Exclusions in odd format
 %!assert (genvarname ("x", {"a", "b"; "x", "d"}), "x1")
 
-%% Test input validation
+## Test input validation
 %!error genvarname ()
 %!error genvarname (1,2,3)
 %!error <more than one STR is given, it must be a cellstr> genvarname (char ("a", "b", "c"))