Adding phpfunction as mentioned by @wouterj

Author: klaussilveira

book/doctrine.rst

@@ -1448,8 +1448,8 @@ using. The following types are supported in Doctrine:
   * ``boolean``
   * ``object`` (serialized and stored in a ``CLOB`` field)
   * ``array`` (serialized and stored in a ``CLOB`` field)
-  * ``simple_array`` (serialized using implode() and explode(), with a comma as delimiter, and stored in a ``CLOB`` field)
-  * ``json_array`` (serialized using json_encode() and json_decode(), and stored in a ``CLOB`` field)
+  * ``simple_array`` (serialized using :phpfunction:`implode()` and :phpfunction:`explode()`, with a comma as delimiter, and stored in a ``CLOB`` field)
+  * ``json_array`` (serialized using :phpfunction:`json_encode()` and :phpfunction:`json_decode()`, and stored in a ``CLOB`` field)
   * ``blob`` (mapped to a resource stream)
   * ``guid``