move zendframework/zend-escaper from require to suggest at Zend\Debug
because only called when we use setEscaper(new \Zend\Escaper\Escaper())
fix Debug::getEscaper() never called at dump() when xdebug is not loaded
Import Escaper as use statement
fix breaks the lazy load of getEscaper
fix cs
added require-dev to composer.json at Zend\Debug
Merge pull request #5240 from samsonasik/fix/escapercall

fix Debug::getEscaper() never called at Debug::dump() when xdebug is loaded
Merge branch 'hotfix/5240'

Close #5240