Issue #3094067 by kishor_kolekar, Suresh Prabhu Parkala, jungle, dpi,…

… xjm: Update missing @param and @return documentation and docs typehints for TypedDataInterface

(cherry picked from commit 84dadf652560cdf21d7ba9e9907d5c47ace5c26f)

lib/Drupal/Core/TypedData/TypedDataInterface.php

@@ -43,6 +43,7 @@ public function getDataDefinition();
    * Gets the data value.
    *
    * @return mixed
+   *   The data value.
    */
   public function getValue();
 
@@ -68,6 +69,7 @@ public function setValue($value, $notify = TRUE);
    * Returns a string representation of the data.
    *
    * @return string
+   *   The string representation of the data.
    */
   public function getString();
 
@@ -105,7 +107,7 @@ public function applyDefaultValue($notify = TRUE);
   /**
    * Returns the name of a property or item.
    *
-   * @return string
+   * @return string|int|null
    *   If the data is a property of some complex data, the name of the property.
    *   If the data is an item of a list, the name is the numeric position of the
    *   item in the list, starting with 0. Otherwise, NULL is returned.