all: drop x/xerrors

ci/run-tests.go

cmd/dif-dump/main.go

cmd/dif-dump/main_test.go

dif/decoder.go

dif/device.go

dif/device_test.go

dif/encoder.go

dif/readout.go

dif/readout_test.go

dif/rw_test.go

go.mod