feature symfony#61564 [Serializer][Validator] Add JSON schema for validating and autocompleting YAML config files (nicolas-grekas)

This PR was merged into the 7.4 branch.

Discussion
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[Serializer][Validator] Add JSON schema for validating and autocompleting YAML config files

| Q             | A
| ------------- | ---
| Branch?       | 7.4
| Bug fix?      | no
| New feature?  | yes
| Deprecations? | no
| Issues        | -
| License       | MIT

Same as symfony#61282 but for serialization and validation metadata.

This provides autocompletion/validation on IDEs that support JSON schema for YAML files, such as phpStorm.

We need to remember updating the serialization schema when context builders are updated.

Commits
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f3ff89a [Serializer][Validator] Add JSON schema for validating and autocompleting YAML config files

Author: fabpot