IS_SUBDIR is subdir a subdirectory of dir?

canonicalization and normalization are NOT performed duplicated slashes are dropped

function s = is_subdir(subdir, dir)
arguments
  subdir {mustBeTextScalar}
  dir {mustBeTextScalar}
end

s = stdlib.drop_slash(subdir);
d = stdlib.drop_slash(dir);

s = startsWith(s, d) && (strlength(s) > strlength(d));

end