Fix: Function wxr_cdata not found.

(szepeviktor/phpstan-wordpress#241)

.distignore

@@ -29,6 +29,7 @@ phpcs.xml.dist
 phpcs.ruleset.xml
 phpstan.neon
 phpstan.neon.dist
+phpstan.stubs
 phpunit.xml
 phpunit.xml.dist
 playwright.config.js

phpstan.neon.dist

@@ -7,11 +7,12 @@ includes:
     - phar://phpstan.phar/conf/bleedingEdge.neon
 
 parameters:
-#    bootstrapFiles:
+    bootstrapFiles:
+        # Constants, functions, etc. used by GatherPress
+        - phpstan.stubs
 #        - vendor/pmc/unit-test/src/classes/autoloader.php
 #        - vendor/autoload.php
 #        - gatherpress.php
-
     parallel:
         maximumNumberOfProcesses: 1
         processTimeout: 300.0

phpstan.stubs

@@ -0,0 +1,17 @@
+<?php
+/**
+ * Constants, functions, etc. used by GatherPress
+ * should be understood by PHPStan.
+ */
+
+namespace {
+    /**
+     * Used in includes/core/classes/class-export.php
+     *
+     * @see https://github.com/szepeviktor/phpstan-wordpress/issues/241
+     *
+     * @param string $str String to wrap in XML CDATA tag.
+     * @return string
+     */
+    function wxr_cdata( string $str ): string {}
+}