completion not work after a line comment at tail

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

NeoVim

### Which OS are you using?

MacOS

### What is the issue affecting?

Completion

### Expected Behaviour

```
obj
:test() -- some comment
:test()
```

the second `test()` should complete as expected

### Actual Behaviour

the second `test()` can not complete

### Reproduction steps

the test lua code:

``` lua
---@meta test

---@class Test
---@overload fun():Test
Test = {}
---@return Test
function Test:test() end

local obj = Test()
obj
:test()
:test() -- comment
:test()
```

### Additional Notes

_No response_

### Log File

_No response_

Reproduce the completion failure in NeoVim using the Lua code in the issue, especially the chained calls with a trailing line comment. Trace the completion path for the second call after the commented line and compare it with the expected behavior. Done means completion works for that call while preserving the existing comment handling.

Written by the indexing model from the issue text.