[13.x] Improve the value types of the Collection put method - #61611

Collection::getOrPut() gives its value its own template and tells PHPStan how the collection changes once the value is stored:

 * @template TGetOrPutValue
 *
 * @param  TKey  $key
 * @param  TGetOrPutValue|(\Closure(): TGetOrPutValue)  $value
 * @return TValue|TGetOrPutValue
 *
 * @phpstan-this-out static<TKey, TValue|TGetOrPutValue>

put(), the plainest way to do the same thing, is still typed against the value type the collection already has, so storing anything else is reported as an error even though the call is perfectly valid:

$users = collect([new User]);

$users->put(1, 'string');

Parameter #2 $value of method Illuminate\Support\Collection<int,User>::put() expects User, string given.

The collection's own type is not updated either, so everything read from it afterwards still looks like the original value type.

This gives put() the same treatment getOrPut() already has: its own template for the stored value, and a @phpstan-this-out describing the widened collection. The assertions added to types/Support/Collection.php cover both the returned collection and the receiver.