Add more types to Template class and compiled templates

tests/Node/BlockTest.php

@@ -33,7 +33,10 @@ class BlockTest extends NodeTestCase
         $tests = [];
         $tests[] = [new BlockNode('foo', new TextNode('foo', 1), 1), <<<EOF
 // line 1
-public function block_foo(\$context, array \$blocks = [])
+/**
+ * @return iterable<string>
+ */
+public function block_foo(array \$context, array \$blocks = []): iterable
 {
     \$macros = \$this->macros;
     yield "foo";