use a more common indentation style

Emacs: M-x customize-option, ruby-deep-indent-paren, remove ?\[ ?\]
Replace Builtins.tointeger

Even though Builtins.tointeger and String#to_i differ very much,
the valid input (0 1 2 3) is handled the same;
"" will become 0 instead of nil which is actually better;
nil cannot happen because @SysconfigDefaults has "0".