Added warning messages in doc block for validateMany and validateAsso…

…ciated about first param being passed by reference

lib/Cake/Model/Model.php

@@ -2100,6 +2100,10 @@ public function saveMany($data = null, $options = array()) {
  * - fieldList: Equivalent to the $fieldList parameter in Model::save()
  * - deep: If set to true, all associated data will be validated as well.
  *
+ * Warning: This method could potentially change the passed argument `$data`,
+ * If you do not want this to happen, make a copy of `$data` before passing it
+ * to this method
+ *
  * @param array $data Record data to validate. This should be a numerically-indexed array
  * @param array $options Options to use when validating record data (see above), See also $options of validates().
  * @return boolean True on success, or false on failure.
@@ -2301,6 +2305,10 @@ public function saveAssociated($data = null, $options = array()) {
  * - fieldList: Equivalent to the $fieldList parameter in Model::save()
  * - deep: If set to true, not only directly associated data , but deeper nested associated data is validated as well.
  *
+ * Warning: This method could potentially change the passed argument `$data`,
+ * If you do not want this to happen, make a copy of `$data` before passing it
+ * to this method
+ *
  * @param array $data Record data to validate. This should be an array indexed by association name.
  * @param array $options Options to use when validating record data (see above), See also $options of validates().
  * @return array|boolean If atomic: True on success, or false on failure.