docs: remove Gitter mentions (#7441)

CONTRIBUTING.md

@@ -1,6 +1,6 @@
 # Contributions Are Welcome!
 
-If you need any help, don't hesitate to ask the community using [GitHub Discussions](https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/discussions/categories/q-a) or [Gitter](https://gitter.im/PHP-CS-Fixer/Lobby).
+If you need any help, don't hesitate to ask the community using [GitHub Discussions](https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/discussions/categories/q-a).
 
 ## Glossary
 

README.md

@@ -85,8 +85,8 @@ Dedicated plugins exist for:
 The PHP CS Fixer is maintained on GitHub at https://github.com/PHP-CS-Fixer/PHP-CS-Fixer.
 Bug reports and ideas about new features are welcome there.
 
-You can reach us at https://gitter.im/PHP-CS-Fixer/Lobby about the project,
-configuration, possible improvements, ideas and questions, please visit us!
+You can reach us in the [GitHub Discussions](https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/discussions/) regarding the
+project, configuration, possible improvements, ideas and questions. Please visit us there!
 
 ## Contribute
 

src/Console/WarningsDetector.php

@@ -70,7 +70,7 @@ final class WarningsDetector
 
         return array_unique(array_merge(
             $this->warnings,
-            ['If you need help while solving warnings, ask at https://gitter.im/PHP-CS-Fixer, we will help you!']
+            ['If you need help while solving warnings, ask at https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/discussions/, we will help you!']
         ));
     }
 }

tests/Console/WarningsDetectorTest.php

@@ -64,7 +64,7 @@ final class WarningsDetectorTest extends TestCase
 
         self::assertSame([
             'You are running PHP CS Fixer installed with old vendor `fabpot/php-cs-fixer`. Please update to `friendsofphp/php-cs-fixer`.',
-            'If you need help while solving warnings, ask at https://gitter.im/PHP-CS-Fixer, we will help you!',
+            'If you need help while solving warnings, ask at https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/discussions/, we will help you!',
         ], $warningsDetector->getWarnings());
     }
 }

tests/Smoke/CiIntegrationTest.php

@@ -159,7 +159,7 @@ Ignoring environment requirements because `PHP_CS_FIXER_IGNORE_ENV` is set. Exec
         $optionalXdebugWarning = 'You are running PHP CS Fixer with xdebug enabled. This has a major impact on runtime performance.
 ';
 
-        $optionalWarningsHelp = 'If you need help while solving warnings, ask at https://gitter.im/PHP-CS-Fixer, we will help you!
+        $optionalWarningsHelp = 'If you need help while solving warnings, ask at https://github.com/PHP-CS-Fixer/PHP-CS-Fixer/discussions/, we will help you!
 
 ';