false positive in count-down-loop

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### 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?

Diagnostics/Syntax Checking

### Expected Behaviour

```lua
local s = -100
for i = s, 1 do
print(i)
end
```

expected no errors

### Actual Behaviour

but got an error from count-down-loop

### Reproduction steps

enable vscode extension and paste code above

### Additional Notes

_No response_

### Log File

_No response_

Reproduce the diagnostic in the Visual Studio Code extension using the Lua snippet in the issue, then locate the source of the count-down-loop diagnostic. Confirm that the example no longer reports an error and add or update coverage if the project has a relevant diagnostic test; the issue does not name a file or test path.

Written by the indexing model from the issue text.