Merge commit '4f0dadbf38ee4cf4cc38cbc232b7708fddf965bc' into staging-…

…next

The "reformat everything on master/staging/staging-next together"
approach from NixOS#322537 didn't quite
work out: master now can't be automatically merged into staging-next
anymore (same for staging-next into staging).

To resolve this, we're performing two merges:
- The first one (see parent commit) to merge the commit on master just before the treewide
  reformat into staging-next
- This one to merge the treewide reformat commit into
  staging-next, but effectively ignoring all changes from the treewide
  reformat commit using `-X ours` when merging (and manually handling
  the few edge cases)