qmlformat does not preserve whitespace in comments and whitespace following header comments

Currently qmlformat doesn't respect REUSE-compliant SPDX header formatting. Ideally, such headers look something like this:

// SPDX-FileCopyrightText: 2023 Joe Smith
//
// SPDX-License-Identifier: GPL-3.0-or-later 

import QtQuick

(In this case, the import statement shows where the actual code begins.)

However, qmlformat will format the above to look like this:

// SPDX-FileCopyrightText: 2023 Joe Smith
// SPDX-License-Identifier: GPL-3.0-or-later
import QtQuick

Ideally, qmlformat would recognize and respect SPDX headers when formatting code.