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/distributions/stdnormal_inv.m
+++ b/scripts/statistics/distributions/stdnormal_inv.m
@@ -46,11 +46,11 @@
 %! x = [-1 0 0.5 1 2];
 %!assert (stdnormal_inv (x), [NaN -Inf 0 Inf NaN])
 
-%% Test class of input preserved
+## Test class of input preserved
 %!assert (stdnormal_inv ([x, NaN]), [NaN -Inf 0 Inf NaN NaN])
 %!assert (stdnormal_inv (single ([x, NaN])), single ([NaN -Inf 0 Inf NaN NaN]))
 
-%% Test input validation
+## Test input validation
 %!error stdnormal_inv ()
 %!error stdnormal_inv (1,2)
 %!error stdnormal_inv (i)