Update wp-config-sample.php for WP Coding Standards

[DrewAPicture]

Per discussion in #19869 thought maybe we should update wp-config.php spacing to coding standards since suggested Multisite defines already adhere to them.

The salts generator would also need to be updated.

As would setup-config.php with a regex that works for both whitespace and not.

There's also a magic number in setup-config.php: $secret_keys[$k] = substr( $v, 28, 64 );

So we'd also need to bump the salts generator version number.

I'd rather just re-open #19869 and remove the spaces from multisite. We have slightly different standards for user-edited files as it is (for example, line endings), and I'd rather not cause confusion or have extra work done over a few spaces in a define() call.

#19869