[clang-tools-extra] [clangd] fix extract-to-function for overloaded operators (PR #81640)

[via cfe-commits]

BenBlumer wrote:

I can confirm this builds and fixes the issue. For example, in: 

```
#include <iostream>

#include <ostream>




int main() {

int a = 5;

int b = 7;

int c;

c =  a+b;

std::cout <<  a+b << std::endl;

return 0;

}
```

Without this patch, there is no refactor available for: 
```
c =  a+b;

std::cout <<  a+b << std::endl
```
With the patch, it can be extracted 


https://github.com/llvm/llvm-project/pull/81640