Update zend.validator.regex.rst
Update zend.validator.regex.rst

Added missing round brackets
rettal/zf2-documentation,samsonasik/zf2-documentation,rettal/zf2-documentation,Rud5G/zf2-documentation,Rud5G/zf2-documentation,akrabat/zf2-documentation,samsonasik/zf2-documentation,akrabat/zf2-documentation