Add test for static-to-static chained call (::) unreachable detection

The previous tests covered static calls chained with instance method
calls (->), but not static calls chained with other static calls (::).
This new test exercises the StaticCallHandler fix where the class
expression is itself a static call with a never-returning argument.

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

Author: phpstan-bot

tests/PHPStan/Rules/DeadCode/UnreachableStatementRuleTest.php

@@ -390,6 +390,10 @@ public function testBug14328(): void
 				'Unreachable statement - code above always terminates.',
 				37,
 			],
+			[
+				'Unreachable statement - code above always terminates.',
+				43,
+			],
 		]);
 	}
 

tests/PHPStan/Rules/DeadCode/data/bug-14328.php

@@ -31,8 +31,14 @@ function testStaticCall(): void {
 	$b = 'this will never run';
 }
 
-function testStaticCallChained(): void {
+function testStaticCallChainedWithMethodCall(): void {
 	$callback = fn (): never => throw new \Exception();
 	$a = Foo::staticReturnSelf($callback())->returnThis('x');
 	$b = 'this will never run either';
 }
+
+function testStaticCallChainedWithStaticCall(): void {
+	$callback = fn (): never => throw new \Exception();
+	$a = Foo::staticReturnSelf($callback())::staticReturnSelf('x');
+	$b = 'this will never run either';
+}