Add support for view types 

View-Type Support: Extend the analysis beyond raw pointers to handle common view/span types that act like non-owning references.

```cpp
std::string_view foo() {
  std::string_view res = a;
  {
    std::string a = "on stack";
    res = a; // warning: does not live long enough.
  }
  std::cout << res;
}
```