Fix shell_open not returning errors on Windows

platform/windows/os_windows.cpp

@@ -557,8 +557,27 @@ String OS_Windows::get_stdin_string(bool p_block) {
 }
 
 Error OS_Windows::shell_open(String p_uri) {
-	ShellExecuteW(nullptr, nullptr, (LPCWSTR)(p_uri.utf16().get_data()), nullptr, nullptr, SW_SHOWNORMAL);
-	return OK;
+	INT_PTR ret = (INT_PTR)ShellExecuteW(nullptr, nullptr, (LPCWSTR)(p_uri.utf16().get_data()), nullptr, nullptr, SW_SHOWNORMAL);
+	if (ret > 32) {
+		return OK;
+	} else {
+		switch (ret) {
+			case ERROR_FILE_NOT_FOUND:
+			case SE_ERR_DLLNOTFOUND:
+				return ERR_FILE_NOT_FOUND;
+			case ERROR_PATH_NOT_FOUND:
+				return ERR_FILE_BAD_PATH;
+			case ERROR_BAD_FORMAT:
+				return ERR_FILE_CORRUPT;
+			case SE_ERR_ACCESSDENIED:
+				return ERR_UNAUTHORIZED;
+			case 0:
+			case SE_ERR_OOM:
+				return ERR_OUT_OF_MEMORY;
+			default:
+				return FAILED;
+		}
+	}
 }
 
 String OS_Windows::get_locale() const {