wp_generate_block_templates_export_file: narrow return type (#451)

Author: IanDelMar

functionMap.php

@@ -244,6 +244,7 @@
     'wp_dropdown_languages' => ["(\$args is array{id: null|''}&array ? void : (\$args is array{name: null|''}&array ? void : string))"],
     'wp_extract_urls' => ['($content is empty ? array{} : list<string>)'],
     'wp_fast_hash' => ['non-falsy-string'],
+    'wp_generate_block_templates_export_file' => ['non-falsy-string|\WP_Error'],
     'wp_generate_password' => [null, '@phpstan-impure' => ''],
     'wp_generate_tag_cloud' => ["(\$args is array{format: 'array'}&array ? array<int, string> : string)"],
     'wp_generate_uuid4' => ['lowercase-string&non-falsy-string', '@phpstan-impure' => ''],

tests/data/return/wp-generate-block-templates-export-file.php

@@ -0,0 +1,7 @@
+<?php
+
+declare(strict_types=1);
+
+use function PHPStan\Testing\assertType;
+
+assertType('non-falsy-string|WP_Error', wp_generate_block_templates_export_file());

wordpress-stubs.php

@@ -99525,6 +99525,7 @@ function wp_is_theme_directory_ignored($path)
      * @since 6.0.0 Adds the whole theme to the export archive.
      *
      * @return WP_Error|string Path of the ZIP file or error on failure.
+     * @phpstan-return non-falsy-string|\WP_Error
      */
     function wp_generate_block_templates_export_file()
     {