[Validator] Added Swedish translations

| Q             | A
| ------------- | ---
| Bug fix?      | [yes]
| New feature?  | [no]
| BC breaks?    | [no]
| Deprecations? | no]
| Tests pass?   | [yes]
| Fixed tickets | [no ticket]
| License       | MIT


Added some missing Swedish translations. 

Should I make an additional PR to `master` for the `trans-unit id=78` ([ref](https://github.com/symfony/symfony/blob/master/src/Symfony/Component/Validator/Resources/translations/validators.en.xlf#L302))? Or should I add that in this PR?