MDL-76034 mod_data: Add type definitions and return values

Type definitions and return values for methods get_field_class_name() and data_get_field()

mod/data/classes/search/entry.php

@@ -373,7 +373,7 @@ class entry extends \core_search\base_mod {
      * @param string $fieldtype
      * @return string|null It will return the class name or null if the field type is not available.
      */
-    protected function get_field_class_name($fieldtype) {
+    protected function get_field_class_name(string $fieldtype) : ?string {
         global $CFG;
 
         $fieldtype = trim($fieldtype);

mod/data/lib.php

@@ -1027,7 +1027,7 @@ function data_get_field_new($type, $data) {
  * @param stdClass|null $cm optional course module data
  * @return data_field_base the field object instance or data_field_base if unkown type
  */
-function data_get_field($field, $data, $cm=null) {
+function data_get_field(stdClass $field, stdClass $data, ?stdClass $cm=null): data_field_base {
     global $CFG;
     if (!isset($field->type)) {
         return new data_field_base($field);