Incorrect type stubs for Memcache

[TysonAndre]

Memcache::get has an incorrect signature in src/Phan/Language/Internal/FunctionSignatureMap.php. So do memcache_get and various other methods
https://www.php.net/manual/en/memcache.get.php

Also, that documentation on php.net is out of date - Memcache::get() is capable of returning many different types

'Memcache::get' => ['array', 'key'=>'string', 'flags='=>'array', 'keys='=>'array'],

Related to websupport-sk/pecl-memcache#64 - real types are extracted from reflection, phpdoc types from various sources

php > $x = new Memcache();
php > $x->addServer('127.0.0.1', 11211);
php > $x->get('test');
php > var_dump($x->get('test'));
bool(false)
php > var_dump($x->set('test', new ArrayObject()));
bool(true)
php > var_dump($x->get('test'));
object(ArrayObject)#2 (1) {
  ["storage":"ArrayObject":private]=>
  array(0) {
  }
}