[Security] Fixed The "nextBytes" Docblock

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | N/A
| License       | MIT
| Doc PR        | N/A

##### This pull request fixes the `nextBytes` docblock in the `SecureRandomInterface`.

There should only be one space following the type in the `@param` annotation.