The original bug report can be found
[here](https://github.com/clangd/clangd/issues/85)
Given the following code:
```c++
void function() {
auto Lambda = [](int a, double &b) {return 1.f;};
La^
}
```
Triggering the completion at `^` would show `(lambda)` before this patch
and would show signature `(int a, double &b) const`, build a snippet etc
with this patch.
Reviewers: sammccall
Reviewed by: sammccall
Differential revision: https://reviews.llvm.org/D70445
Kirill Bobyrev