'@operator call' only supports a single argument

### 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

### Expected Behaviour

When using the
```
---@operator call([...])
```
annotation, any number of arguments should be permitted, like with the normal `fun([...])` annotation.

### Actual Behaviour

Writing something like
```
---@operator call(string, string)
```
causes a syntax error,

### Reproduction steps

1. Define a custom class with a custom `@operator call` annotation:
```
---@class MyTestClass
---@operator call(string, string)
```

### Additional Notes

The exact error is: `')' expected.Lua Syntax Check.(luadoc-miss-symbol)`

### Log File

_No response_

Start by reproducing the supplied `MyTestClass` example and searching the annotation handling for `@operator call`. Done means the two-argument annotation is accepted without `luadoc-miss-symbol`, while the existing single-argument form continues to work.

Written by the indexing model from the issue text.