Improve error message when a service is missing and ServiceSubscriberInterface/a ServiceLocator is used #25196
Description
| Q | A |
|---|---|
| Bug report? | DX one |
| Feature request? | no |
| BC Break report? | no |
| RFC? | yes |
| Symfony version | 3.4/3.3 |
As seen in #25194, it can be hard for newcomers to know why $this->get(Some::class) doesn't work.
In a "failure driven development" spirit, we should improve the message, so that ppl can resolve that on their own.