Release Notes:

  - Improved C and C++ syntax highlighting.

| Zed 0.174.6 | With this PR |
| --- | --- |
|
![Image](https://github.com/user-attachments/assets/fa5bf2e0-c682-4e6a-ab64-bb873579d47c)
|
![Image](https://github.com/user-attachments/assets/dc980de9-cd6a-4b0b-8ddc-ac705f687910)
|

- `NULL`, `nullptr`: `constant` -> `constant.builtin`

```cpp
#include <stdbool.h>
int a[] = {true, false};
const int * IDENTIFIER = nullptr;
```

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Co-authored-by: Marshall Bowers <git@maxdeviant.com>