minor #33289 [DomCrawler] Fix FileFormField PHPDoc (dunglas)

This PR was squashed before being merged into the 3.4 branch (closes #33289).

Discussion
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[DomCrawler] Fix FileFormField PHPDoc

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no <!-- please update UPGRADE-*.md and src/**/CHANGELOG.md files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

`null` is a valid value, it is used in case of errors. Then the parent class must allow `null` values too. I think it's important regarding the ongoing process of adding typehints everywhere.

Commits
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162bfc3cad [DomCrawler] Fix FileFormField PHPDoc

Author: fabpot

Field/ChoiceFormField.php

@@ -113,7 +113,7 @@ public function untick()
     /**
      * Sets the value of the field.
      *
-     * @param string|array $value The value of the field
+     * @param string|array|bool $value The value of the field
      *
      * @throws \InvalidArgumentException When value type provided is not correct
      */

Field/FileFormField.php

@@ -48,7 +48,7 @@ public function upload($value)
     /**
      * Sets the value of the field.
      *
-     * @param string $value The value of the field
+     * @param string|null $value The value of the field
      */
     public function setValue($value)
     {

Field/FormField.php

@@ -99,7 +99,7 @@ public function getValue()
     /**
      * Sets the value of the field.
      *
-     * @param string $value The value of the field
+     * @param string|array|bool|null $value The value of the field
      */
     public function setValue($value)
     {