Issue #2926479 by bhanuprakashnani, mohit1604, joachim: incorrectly formatted...

Issue #2926479 by bhanuprakashnani, mohit1604, joachim: incorrectly formatted docs in mainPropertyName()

core/lib/Drupal/Core/Field/FieldItemInterface.php

@@ -38,8 +38,8 @@ public static function propertyDefinitions(FieldStorageDefinitionInterface $fiel
    * Returns the name of the main property, if any.
    *
    * Some field items consist mainly of one main property, e.g. the value of a
-   * text field or the @code target_id @endcode of an entity reference. If the
-   * field item has no main property, the method returns NULL.
+   * text field or the target_id of an entity reference. If the field item has
+   * no main property, the method returns NULL.
    *
    * @return string|null
    *   The name of the value property, or NULL if there is none.