File::isReference(): bug fix - arrow function params passed by reference

The `&` for parameters passed by reference in an arrow function declaration were incorrectly not recognized as references.

This is the root cause of issue 3049, which affected the `PSR12.Operators.OperatorSpacing` and the `Squiz.WhiteSpace.OperatorSpacing` sniffs (and possibly/probably more sniffs).

Includes unit test.

Fixes 3049

src/Files/File.php

@@ -1981,6 +1981,7 @@ public function isReference($stackPtr)
                 $owner = $this->tokens[$this->tokens[$lastBracket]['parenthesis_owner']];
                 if ($owner['code'] === T_FUNCTION
                     || $owner['code'] === T_CLOSURE
+                    || $owner['code'] === T_FN
                 ) {
                     $params = $this->getMethodParameters($this->tokens[$lastBracket]['parenthesis_owner']);
                     foreach ($params as $param) {

src/Standards/PSR12/Tests/Operators/OperatorSpacingUnitTest.inc

@@ -56,3 +56,6 @@ function name($a = -1) {}
 
 $a =& $ref;
 $a = [ 'a' => &$something ];
+
+$fn = fn(array &$one) => 1;
+$fn = fn(array & $one) => 1;

src/Standards/PSR12/Tests/Operators/OperatorSpacingUnitTest.inc.fixed

@@ -56,3 +56,6 @@ function name($a = -1) {}
 
 $a =& $ref;
 $a = [ 'a' => &$something ];
+
+$fn = fn(array &$one) => 1;
+$fn = fn(array & $one) => 1;

tests/Core/File/IsReferenceTest.inc

@@ -140,5 +140,11 @@ $closure = function() use (&$var){};
 /* testArrowFunctionReturnByReference */
 fn&($x) => $x;
 
+/* testArrowFunctionPassByReferenceA */
+$fn = fn(array &$one) => 1;
+
+/* testArrowFunctionPassByReferenceB */
+$fn = fn($param, &...$moreParams) => 1;
+
 /* testClosureReturnByReference */
 $closure = function &($param) use ($value) {};

tests/Core/File/IsReferenceTest.php

@@ -228,6 +228,14 @@ public function dataIsReference()
                 '/* testArrowFunctionReturnByReference */',
                 true,
             ],
+            [
+                '/* testArrowFunctionPassByReferenceA */',
+                true,
+            ],
+            [
+                '/* testArrowFunctionPassByReferenceB */',
+                true,
+            ],
             [
                 '/* testClosureReturnByReference */',
                 true,