minor #26565 [BrowserKit] Fix Cookie's PHPDoc (dunglas)

This PR was merged into the 2.7 branch.

Discussion
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[BrowserKit] Fix Cookie's PHPDoc

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| 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 files -->
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | n/a   <!-- #-prefixed issue number(s), if any -->
| License       | MIT
| Doc PR        | n/a

Commits
-------

4ac5d3c [BrowserKit] Fix Cookie's PHPDoc

src/Symfony/Component/BrowserKit/Cookie.php

@@ -44,14 +44,14 @@ class Cookie
     /**
      * Sets a cookie.
      *
-     * @param string $name         The cookie name
-     * @param string $value        The value of the cookie
-     * @param string $expires      The time the cookie expires
-     * @param string $path         The path on the server in which the cookie will be available on
-     * @param string $domain       The domain that the cookie is available
-     * @param bool   $secure       Indicates that the cookie should only be transmitted over a secure HTTPS connection from the client
-     * @param bool   $httponly     The cookie httponly flag
-     * @param bool   $encodedValue Whether the value is encoded or not
+     * @param string      $name         The cookie name
+     * @param string      $value        The value of the cookie
+     * @param string|null $expires      The time the cookie expires
+     * @param string|null $path         The path on the server in which the cookie will be available on
+     * @param string      $domain       The domain that the cookie is available
+     * @param bool        $secure       Indicates that the cookie should only be transmitted over a secure HTTPS connection from the client
+     * @param bool        $httponly     The cookie httponly flag
+     * @param bool        $encodedValue Whether the value is encoded or not
      */
     public function __construct($name, $value, $expires = null, $path = null, $domain = '', $secure = false, $httponly = true, $encodedValue = false)
     {
@@ -112,8 +112,8 @@ public function __toString()
     /**
      * Creates a Cookie instance from a Set-Cookie header value.
      *
-     * @param string $cookie A Set-Cookie header value
-     * @param string $url    The base URL
+     * @param string      $cookie A Set-Cookie header value
+     * @param string|null $url    The base URL
      *
      * @return static
      *
@@ -242,7 +242,7 @@ public function getRawValue()
     /**
      * Gets the expires time of the cookie.
      *
-     * @return string The cookie expires time
+     * @return string|null The cookie expires time
      */
     public function getExpiresTime()
     {