Remove interface typehint in Factory::addParserFactory
Remove interface typehint in Factory::addParserFactory

This fixes the following tests from TheSeer\phpDox\Tests\Unit\DocBlock\FactoryTest:

- testAddParserFactory
- testAddParserFactoryExpectingFactoryException

The change tries to be in conformance with the changes from commit 66c58d0c7e.
tucompualdia/phpdox,FireWalkerX/phpdox,tucompualdia/phpdox,sanduhrs/phpdox,sanduhrs/phpdox,fxstein/phpdox,FireWalkerX/phpdox,fxstein/phpdox