Fix block helper non-list array stringification

Author: theodorejb

src/Runtime.php

@@ -568,7 +568,7 @@ private static function resolveBlockResult(RuntimeContext $cx, mixed $result, mi
 
         // Arrays stringify like JS Array.prototype.toString(), regardless of fn block.
         if (is_array($result)) {
-            return implode(',', $result);
+            return self::raw($result);
         }
 
         if ($cb === null) {

tests/RegressionTest.php

@@ -767,8 +767,13 @@ public static function helperProvider(): array
             ],
             'block helper returning truthy non-string: stringified like JS' => [
                 'template' => '{{#helper}}block{{/helper}}',
-                'helpers' => ['helper' => fn() => ['truthy', 'array']],
-                'expected' => 'truthy,array',
+                'helpers' => ['helper' => fn() => ['a', ['ba', 'bb'], 'c']],
+                'expected' => 'a,ba,bb,c',
+            ],
+            'block helper returning non-list array: stringified like JS' => [
+                'template' => '{{#helper}}block{{/helper}}',
+                'helpers' => ['helper' => fn() => ['a' => 'foo', 'b' => 'bar']],
+                'expected' => '[object Object]',
             ],
             'inverted known block helper returning truthy non-string: stringified like JS' => [
                 'template' => '{{^helper}}block{{/helper}}',