[2.3] Docblocks should not be followed by a blank line
minor #12993 [2.3] Docblocks should not be followed by a blank line (GrahamCampbell)

This PR was squashed before being merged into the 2.3 branch (closes #12993).

Discussion
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[2.3] Docblocks should not be followed by a blank line

| 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

There should be no blank line(s) between phpdocs that document properties, interfaces, classes, functions, or traits. This pull request was a test run of a new php-cs-fixer: https://github.com/FriendsOfPHP/PHP-CS-Fixer/pull/864.

Commits
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4e7ba1b [2.3] Docblocks should not be followed by a blank line
[Tests] Silenced all deprecations in tests for 2.3
Merge branch '2.3' into 2.5

* 2.3:
  [Config] adds missing « use » statement for InvalidTypeException type hint in documentation.
  [Config] fixes broken unit test on ArrayNode class.
  fixed CS
  [Security] Delete old session on auth strategy migrate
  update required minimum TwigBridge version
  Very minor grammar fix in error message
  [Tests] Silenced all deprecations in tests for 2.3
  BinaryFileResponse - add missing newline
  fixed CS
  add a limit and a test to FlattenExceptionTest.
  CS: There should be no empty lines following phpdocs
  [FrameworkBundle] fix cache:clear command
  [2.3] Docblocks should not be followed by a blank line
  Fix return phpdoc
  [PropertyAccess] Added test to verify #5775 is fixed

Conflicts:
	src/Symfony/Bundle/TwigBundle/composer.json
	src/Symfony/Component/PropertyAccess/Tests/PropertyAccessorTest.php
	src/Symfony/Component/Security/Core/Tests/Validator/Constraints/UserPasswordValidatorTest.php