minor #54460 [Validator] Update internal phpdoc (alamirault)

This PR was merged into the 7.1 branch.

Discussion
----------

[Validator] Update internal phpdoc

| Q             | A
| ------------- | ---
| Branch?       | 7.1
| Bug fix?      | no
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Issues        | Fix #... <!-- prefix each issue number with "Fix #", no need to create an issue if none exists, explain below instead -->
| License       | MIT

Symfony 2.5 was released [10 years ago.](https://symfony.com/releases/2.5)

I think we can update this phpdoc 😄

Commits
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cd2bc5f711 [Validator] Update internal phpdoc

Author: xabbuh

Context/ExecutionContext.php

@@ -33,7 +33,7 @@
  *
  * @see ExecutionContextInterface
  *
- * @internal since version 2.5. Code against ExecutionContextInterface instead.
+ * @internal
  */
 class ExecutionContext implements ExecutionContextInterface
 {

Violation/ConstraintViolationBuilder.php

@@ -22,7 +22,7 @@
  *
  * @author Bernhard Schussek <bschussek@gmail.com>
  *
- * @internal since version 2.5. Code against ConstraintViolationBuilderInterface instead.
+ * @internal
  */
 class ConstraintViolationBuilder implements ConstraintViolationBuilderInterface
 {