shell32: Add stub for SetCurrentProcessExplicitAppUserModelID.

dlls/shell32/shell32.spec

@@ -324,6 +324,7 @@
 @ stub RealShellExecuteExW
 @ stub RealShellExecuteW
 @ stub RegenerateUserEnvironment
+@ stdcall SetCurrentProcessExplicitAppUserModelID(wstr)
 @ stdcall SHAddToRecentDocs (long ptr)
 @ stdcall SHAppBarMessage(long ptr)
 @ stdcall SHBindToParent(ptr ptr ptr ptr)

dlls/shell32/shell32_main.c

@@ -1283,3 +1283,9 @@ HRESULT WINAPI SHGetLocalizedName(LPCWSTR path, LPWSTR module, UINT size, INT *r
     FIXME("%s %p %u %p: stub\n", debugstr_w(path), module, size, res);
     return E_NOTIMPL;
 }
+
+HRESULT WINAPI SetCurrentProcessExplicitAppUserModelID(PCWSTR appid)
+{
+    FIXME("%s: stub\n", debugstr_w(appid));
+    return E_NOTIMPL;
+}