Fixed bug in session manager code example

Changed ->container into
Merge branch 'version/bump'

Bump to 2.3.3dev
Merge branch 'fix/zend.session.manager.rst' of github.com:Martin-P/zf2-documentation into Martin-P-fix/zend.session.manager.rst
Merge branch 'Martin-P-fix/zend.session.manager.rst' into develop

Forward port #1342