minor #28675 [CS] Enforces null type hint on last position in phpDocs (carusogabriel)

This PR was merged into the 2.8 branch.

Discussion
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[CS] Enforces null type hint on last position in phpDocs

| Q             | A
| ------------- | ---
| Branch?       | 2.8
| Bug fix?      | no
| New feature?  | no <!-- don't forget to update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- don't forget to update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | -   <!-- #-prefixed issue number(s), if any -->
| License       | MIT
| Doc PR        | - <!-- required for new features -->

As a majority in our codebase, the `null` typehint usually comes in the last position in phpDocs.

Commits
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efbba25577 [CS] Enforces null type hint on last position in phpDocs

Author: nicolas-grekas

Command/Command.php

@@ -140,7 +140,7 @@ protected function configure()
      * execute() method, you set the code to execute by passing
      * a Closure to the setCode() method.
      *
-     * @return null|int null or 0 if everything went fine, or an error code
+     * @return int|null null or 0 if everything went fine, or an error code
      *
      * @throws LogicException When this abstract method is not implemented
      *

Helper/QuestionHelper.php

@@ -109,7 +109,7 @@ public function getName()
      *
      * This method is public for PHP 5.3 compatibility, it should be private.
      *
-     * @return bool|mixed|null|string
+     * @return bool|mixed|string|null
      *
      * @throws RuntimeException In case the fallback is deactivated and the response cannot be hidden
      */

Question/Question.php

@@ -117,7 +117,7 @@ public function setHiddenFallback($fallback)
     /**
      * Gets values for the autocompleter.
      *
-     * @return null|iterable
+     * @return iterable|null
      */
     public function getAutocompleterValues()
     {
@@ -127,7 +127,7 @@ public function getAutocompleterValues()
     /**
      * Sets values for the autocompleter.
      *
-     * @param null|iterable $values
+     * @param iterable|null $values
      *
      * @return $this
      *
@@ -156,7 +156,7 @@ public function setAutocompleterValues($values)
     /**
      * Sets a validator for the question.
      *
-     * @param null|callable $validator
+     * @param callable|null $validator
      *
      * @return $this
      */
@@ -170,7 +170,7 @@ public function setValidator($validator)
     /**
      * Gets the validator for the question.
      *
-     * @return null|callable
+     * @return callable|null
      */
     public function getValidator()
     {
@@ -182,7 +182,7 @@ public function getValidator()
      *
      * Null means an unlimited number of attempts.
      *
-     * @param null|int $attempts
+     * @param int|null $attempts
      *
      * @return $this
      *
@@ -204,7 +204,7 @@ public function setMaxAttempts($attempts)
      *
      * Null means an unlimited number of attempts.
      *
-     * @return null|int
+     * @return int|null
      */
     public function getMaxAttempts()
     {