Should `GUID_NULL` really be in `windows::Win32::Media::KernelStreaming`?

### Suggestion

[`Shell_NotifyIconGetRect()`](https://learn.microsoft.com/en-us/windows/win32/api/shellapi/nf-shellapi-shell_notifyicongetrect) demands `GUID_NULL` for its struct parameter [`NOTIFYICONIDENTIFIER`](https://learn.microsoft.com/en-us/windows/win32/api/shellapi/ns-shellapi-notifyiconidentifier), which has nothing to to with `windows::Win32::Media::KernelStreaming` that `GUID_NULL` currently [resides in](https://microsoft.github.io/windows-docs-rs/doc/windows/Win32/Media/KernelStreaming/constant.GUID_NULL.html).

Should a user wanting to use the shell API really have to add a dependency to this module? [`GUID`](https://microsoft.github.io/windows-docs-rs/doc/windows/core/struct.GUID.html) is even from `windows::core`!

Start with the linked Shell_NotifyIconGetRect and NOTIFYICONIDENTIFIER documentation, then inspect the generated windows::Win32::Media::KernelStreaming::GUID_NULL location and windows::core::GUID references. Done means deciding and implementing an appropriate metadata location so shell API users do not need a KernelStreaming dependency, with generated bindings and documentation remaining consistent.

Written by the indexing model from the issue text.