Add example snippet to make taxonomies private to the developer docs

Author: theskinnyghost

hookdocs/meta.json

@@ -1,4 +1,7 @@
 {
+    "useful-snippets": {
+      "title": "Useful snippets"
+    },
     "wp-cli": {
         "title": "WP-CLI Commands"
     }

hookdocs/useful-snippets.md

@@ -0,0 +1,18 @@
+## Make ClassifAI taxonomies private
+
+Some users might want to set some of the taxonomies provided by the plugin private, so that their archive pages won't be generated (and thus indexed by search engines).
+
+In order to do that, we can use a filter provided by WordPress Core, namely `register_{$taxonomy}_taxonomy_args` ([see here for the documentation](https://developer.wordpress.org/reference/hooks/register_taxonomy_taxonomy_args/)).
+
+For example, let's say we want to make the `classifai-image-tags` taxonomy private, we would need to add this snippet to either our theme `functions.php` or our custom plugin.
+
+```php
+namespace MyPluginOrTheme;
+
+add_filter( 'register_classifai-image-tags_taxonomy_args', __NAMESPACE__ . '\override_taxonomy_args' );
+
+function override_taxonomy_args( $args ) {
+	$args['public'] = false;
+	return $args;
+}
+```