Absent alignment requirements for the CONTEXT struct

### Which crate is this about?

windows, windows-sys

### Crate version

_No response_

### Summary

According to the definition in the Windows.h, the CONTEXT struct must be aligned by 16 bytes, but it is not neither in windows_rs, nor in windows_sys (it's just a #[repr(C)] here).
It causes an ERROR_NOACCESS errors in the GetThreadContext()/SetThreadContext() functions.

### Toolchain version/configuration

_No response_

### Reproducible example

_No response_

### Crate manifest

_No response_

### Expected behavior

_No response_

### Actual behavior

_No response_

### Additional comments

_No response_