[DOCS] Fix wrong code example using :php instead of ::class

Resolves: #101938
Releases: main, 12.4
Change-Id: I8def061d7188a4d247a832247c01cdddd745c7dc
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/81054
Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>

typo3/sysext/core/Documentation/Changelog/12.2/Feature-99618-ListOfCountriesInTheWorldAndTheirLocalizedNames.rst

@@ -30,7 +30,7 @@ It is now possible to load a list of all countries via PHP:
 
     use TYPO3\CMS\Core\Utility\GeneralUtility;
 
-    $countryProvider = GeneralUtility::makeInstance(CountryProvider:php);
+    $countryProvider = GeneralUtility::makeInstance(CountryProvider::class);
     $france = $countryProvider->getByIsoCode('FR');
     // or
     $france = $countryProvider->getByEnglishName('France');