Improve docs for AMP_Tag_And_Attribute_Sanitizer::process_node()

includes/sanitizers/class-amp-tag-and-attribute-sanitizer.php

@@ -350,7 +350,10 @@ private function get_rule_spec_list_to_validate( $node, $rule_spec ) {
 	}
 
 	/**
-	 * Process a node by sanitizing and/or validating it per.
+	 * Process a node by checking if an element and its attributes are valid, and removing them when invalid.
+	 *
+	 * Attributes which are not valid are removed. Elements which are not allowed are also removed,
+	 * including elements which miss mandatory attributes.
 	 *
 	 * @param DOMNode $node Node.
 	 */