With shortcuts initialization

### Short description

I tried to select whole article with shortcut cmd a, but shortcuts are not even initialized

### Actual behaviour

create shortcut on not only rendered articles, but for all note class initialization

### Steps to reproduce

1. Create a new Note
2. Click on [...]
3. [...]

### On which platforms did you notice this

This issue annoys me on [macOS 10.13].

### App version

I use CodeX Notes [v1.0].

### Image

Add any image that might be helpful to understand the problem.

Start by tracing Note creation and the shortcut initialization path described in the issue. Reproduce the macOS 10.13 behavior by creating a new Note and using the Cmd+A shortcut; done means shortcuts are initialized for every Note, including notes that are not yet rendered.

由索引模型根据 Issue 内容生成。