Apply patch from failing clangtidyfull:linux job

some pipeline (i guess the branch one, since MRs are still passing/approving) fails because the clang-tidy full job fails - because now that we use C++20, it expects older constructs to be replaced with newer ones (e.g. reverse iterators with views::reverse)

This commit applies the patch suggested in the output of said job: copied and pasted into a patch file, with whitespace errors reported by first attempt at git apply fixed, actually applied, and augmented by one now-missing forward-declaration resulting from shuffling #includes.