Suggest [[clang::lifetimebound]] for implicit this parameter

[usx95]

struct S {
  const S& get() { return *this; }
};

struct T {
  std::string data;
  std::string_view getView() { return data; }
}

Expected suggestions:

const S& get() [[clang::lifetimebound]] { return *this; }
std::string_view getView() [[clang::lifetimebound]] { return data; }

[llvmbot]

@llvm/issue-subscribers-clang-temporal-safety

Author: Utkarsh Saxena (usx95)

```cpp struct S { const S& get() { return *this; } };

struct T {
std::string data;
std::string_view getView() { return data; }
}

Expected suggestions:
```cpp
const S& get() [[clang::lifetimebound]] { return *this; }
std::string_view getView() [[clang::lifetimebound]] { return data; }