Copyright statements and license identifiers appear in the HTML

Some pages are showing copyright statements and license identifiers in the rendered output, typically like this:

// Copyright (C) 2020 The Qt Company Ltd. // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only

These appear in at least the doc pages for qt_finalize_project() and qt_add_executable().

The doc sources in qtbase contain \include commands and the text appears above them in the generated HTML: \qtbase\src\corelib\doc\src\cmake\qt_finalize_project.qdoc:42

The \include files need to be changed to use snippet markers and those need to be used in the docs.