[Serializer] Name Converter

| Q                | A
| --------------- | ---
| Doc fix?      | no
| New docs? | yes symfony/symfony#13120
| Applies to   | 2.7

This is the documentation for the Serializer Name Converter feature.
I don't think it's OK to use a real company name and address. What about using `ACME` as the rest of the documentation?