Support for autocompletion rules in FormRequest

[N1ebieski]

Fixes #291, #474

This PR adds autocompletion rules names in FormRequest::rules method. It works for Livewire Forms as well.

This PR depends on laravel/vs-code-php-parser-cli#16 and requires much more testing.

[TitasGailius]

@N1ebieski thanks! This looks good to go.

Before we merge, could you share a quick example of when this check is needed?

this.result.parent?.type !== "array_item"

[N1ebieski]

@TitasGailius this is necessary because if you start writing a rule for a field name, for example:

public function rules(): array
    {
        return [
            'id' => ['
        ];
    }

then inside fillingInArrayKey you will get:

As you see the result.parent.type is array_item. This is how we recognize that a user is trying to write a rule name. If you remove this condition, then this condition will evaluate to true.

For comparison, here is the scenario when a user starts writing a field name:

public function rules(): array
    {
        return [
            '
        ];
    }

As you see, result.parent.type is methodCall, so the extension knows that this is not a place for a rule name.

[TitasGailius]

Thanks!