Hotfix: fn arrow closure - Squiz.Scope.StaticThisUsage

Related #2523

I am not sure about this change as this is actually invalid code.
We cannot use `$this` even inside closure, as then closure is not gonna
be usable. The same in case of normal closure.

Maybe here we should have another fix then?

Author: michalbundyra

src/Standards/Squiz/Sniffs/Scope/StaticThisUsageSniff.php

@@ -69,10 +69,11 @@ public function processTokenWithinScope(File $phpcsFile, $stackPtr, $currScope)
         $end  = $tokens[$stackPtr]['scope_closer'];
 
         do {
-            $next = $phpcsFile->findNext([T_VARIABLE, T_CLOSURE, T_ANON_CLASS], ($next + 1), $end);
+            $next = $phpcsFile->findNext([T_VARIABLE, T_CLOSURE, T_FN, T_ANON_CLASS], ($next + 1), $end);
             if ($next === false) {
                 continue;
             } else if ($tokens[$next]['code'] === T_CLOSURE
+                || $tokens[$next]['code'] === T_FN
                 || $tokens[$next]['code'] === T_ANON_CLASS
             ) {
                 $next = $tokens[$next]['scope_closer'];

src/Standards/Squiz/Tests/Scope/StaticThisUsageUnitTest.inc

@@ -75,4 +75,8 @@ $b = new class()
 	public static function myFunc() {
 		$this->doSomething();
 	}
+
+	public static function other() {
+	    return fn () => $this->name;
+    }
 }