[DependencyInjection] enhanced some error messages
merged branch fabpot/better-exception-messages (PR #6994)

This PR was merged into the 2.2 branch.

Commits
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3053194 [DependencyInjection] enhanced some error messages

Discussion
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[DependencyInjection] enhanced some error messages

| 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