There's nothing going on with behavior here that would prevent these
from being const qualified.
Also better communicates that this function isn't intended to modify the
given resource pack.
SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
The pack is already has its validity checked at the beginning of the
function, so we don't need to check this again after inserting it.
Also resolves a use-after-move case.
Lioncash