Return the text value in _ array key

If element has attributes & string value until now the string value was ignored & lost, I added the _ index so that it also returns the string value along with the attribute names
Fix CS + reduce branch depth
Reproducing test case for #6279
#6279 - #6879 - minor CS fixes
Merge branch 'hotfix/#6279-#6879-zend-config-reader-xml-node-value-conflict'

Close #6279
Close #6879
Preserve the fluent interface
#6398 - minor CS fixes (spacing, return type)
#6398 - minor CS fixes (spacing, return type)
#6398 - type fix (`listenersToDetach` may be `null`)
#6398 - test case to enforce fluent interface on `Forward#setListenersToDetach()`
#6398 - Adding missing test-case properties and type-hints
Merge branch 'hotfix/#6398-forward-controller-plugin-fluent-interface-consistency'

Close #6398
PHPCS fixes for Zend\Di