Cast on global results in unknown type conversion

還沒有人認領這個 Issue。

### How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

### Which OS are you using?

Windows

### What is the issue affecting?

Annotations, Diagnostics/Syntax Checking

### Expected Behaviour

Using `---@cast` on a global variable behaves the same as for a local variable.

### Actual Behaviour


### Reproduction steps

```
---@type integer
TestingValue = 1
---@cast TestingValue +number
```

### Additional Notes

_No response_

### Log File

[Projects_Lua.zip](https://github.com/sumneko/lua-language-server/files/9739798/Projects_Lua.zip)

首先使用 Visual Studio Code 擴充功能在 Lua 程式碼片段中重現回報的診斷，然後追蹤 `---@cast` 註解如何處理全域 `TestingValue`，並將其與區域變數進行比較。完成的標準是，對全域變數進行轉型時不再回報未知的型別轉換，且其行為與區域變數的情況一致。

由索引模型根據 Issue 內容生成。