Docs: Update parameter types to allow null for interactivity api functions

When [58327] added annotations for a nullable-typed argument in the Interactivity API, the PHPDoc comment wasn’t also updated. This patch adds the corresponding documentation update.

Prepared ahead of WCEU 2026, merged as part of Contributor Day.

Developed in: WordPress#11470
Discussed in: https://core.trac.wordpress.org/ticket/65404

Follow-up to [58327].

Props audrasjb, mukesh27, soean.
Fixes #65404.


git-svn-id: https://develop.svn.wordpress.org/trunk@62458 602fd350-edb4-49c9-b593-d223f7449a82

Author: dmsnell

src/wp-includes/interactivity-api/class-wp-interactivity-api.php

@@ -138,8 +138,8 @@ final class WP_Interactivity_API {
 	 * @since 6.5.0
 	 * @since 6.6.0 The `$store_namespace` param is optional.
 	 *
-	 * @param string $store_namespace Optional. The unique store namespace identifier.
-	 * @param array  $state           Optional. The array that will be merged with the existing state for the specified
+	 * @param string|null $store_namespace Optional. The unique store namespace identifier.
+	 * @param array|null  $state           Optional. The array that will be merged with the existing state for the specified
 	 *                                store namespace.
 	 * @return array The current state for the specified store namespace. This will be the updated state if a $state
 	 *               argument was provided.
@@ -311,7 +311,7 @@ public function filter_script_module_interactivity_data( array $data ): array {
 	 *
 	 * @since 6.6.0
 	 *
-	 * @param string $store_namespace Optional. The unique store namespace identifier.
+	 * @param string|null $store_namespace Optional. The unique store namespace identifier.
 	 */
 	public function get_context( ?string $store_namespace = null ): array {
 		if ( null === $this->context_stack ) {

src/wp-includes/interactivity-api/interactivity-api.php

@@ -53,9 +53,9 @@ function wp_interactivity_process_directives( string $html ): string {
  * @since 6.5.0
  * @since 6.6.0 The namespace can be omitted when called inside derived state getters.
  *
- * @param string $store_namespace The unique store namespace identifier.
- * @param array  $state           Optional. The array that will be merged with the existing state for the specified
- *                                store namespace.
+ * @param string|null $store_namespace The unique store namespace identifier.
+ * @param array       $state           Optional. The array that will be merged with the existing state for the specified
+ *                                     store namespace.
  * @return array The state for the specified store namespace. This will be the updated state if a $state argument was
  *               provided.
  */
@@ -119,7 +119,7 @@ function wp_interactivity_data_wp_context( array $context, string $store_namespa
  *
  * @since 6.6.0
  *
- * @param string $store_namespace Optional. The unique store namespace identifier.
+ * @param string|null $store_namespace Optional. The unique store namespace identifier.
  * @return array The context for the specified store namespace.
  */
 function wp_interactivity_get_context( ?string $store_namespace = null ): array {