Use single quotes for strings without special escape sequences in CallCallablesRuleTest

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 2 people

tests/PHPStan/Rules/Functions/CallCallablesRuleTest.php

@@ -382,15 +382,15 @@ public function testBug4510(): void
 				16,
 			],
 			[
-				"Trying to invoke array{Bug4510\HelloWorld, string} but it might not be a callable.",
+				'Trying to invoke array{Bug4510\HelloWorld, string} but it might not be a callable.',
 				27,
 			],
 			[
 				"Trying to invoke array{'Bug4510\\\HelloWorld', string} but it might not be a callable.",
 				46,
 			],
 			[
-				"Trying to invoke array{Bug4510\HelloWorld, string} but it might not be a callable.",
+				'Trying to invoke array{Bug4510\HelloWorld, string} but it might not be a callable.',
 				90,
 			],
 		]);