[Scoper] Handle callables

[theofidry]

e.g.:

if ($type & self::OUTPUT_RAW) {
                $messages = \array_map(['Symfony\Component\Console\Formatter\OutputFormatter', 'escape'], $messages);
            }

return \call_user_func_array(array('Symfony\\Component\\Debug\\Exception\\FlattenException', $method), $args);

This peculiar case could be part of #286, but more generally I believe such strings should be scoped properly. without much risks

[theofidry]

There is quite a few more cases that could be handled, in general I think to better handle it it would be worth leveraging the JetBrains' stubs to apply it to callable types in general.

Unfortunately treating user code is likely a lot more tricky as this would require reflection which would significantly slow down the process.

[theofidry]

Closing this. It's a nice to have that I'm unlikely to ever implement myself and no one came forward to propose something in 5 years.

Moreover, it is not possible to use callables with the spread operator in PHP completely removing this problem.