Method, type or constant "WIMMountImage" not found

## Actual behavior

> NativeMethods.txt(1,1): Warning PInvoke001 : Method, type or constant "WIMMountImage" not found

## Expected behavior

Should generate the wrapper

## Repro steps

1. `NativeMethods.txt` content:
```
WIMMountImage
WIMUnmountImage
```

### Context

- CsWin32 version: `0.3.106`
- Win32Metadata version (if explicitly set by project): `net8.0-windows10.0.19041.0`
- Target Framework: `net8.0-windows10.0.19041.0`
- `LangVersion` (if explicitly set by project):

Start by checking how Win32Metadata exposes WIMMountImage and WIMUnmountImage to CsWin32, using the NativeMethods.txt reproduction. Done means both names are recognized without PInvoke001 and the generator emits their wrappers.

Written by the indexing model from the issue text.