Mostly automated fixes from running:
```
go run golang.org/x/tools/go/analysis/passes/modernize/cmd/modernize@latest --fix ./...
```
But carefully reviewed, and several fixes reverted as they looked like
they potentially could be less performant, and in a few cases due to
bugs in the analyzer that changed semantics of the code. Will report
these upstream.
Mostly good fixes though!
Signed-off-by: Anders Eknert <anders.eknert@apple.com>