cmd/cue: make fmt work on tool files

cue fmt now always selects all CUE files
for formatting, regardless of package or
files mode.

Change-Id: I725461575cb0799ab3ae1f481b13b2a55df7cf97
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/4480
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/cmd/cue/cmd/fmt.go b/cmd/cue/cmd/fmt.go
index 8e6ee1a..810ddec 100644
--- a/cmd/cue/cmd/fmt.go
+++ b/cmd/cue/cmd/fmt.go
@@ -31,7 +31,10 @@
 		Long: `Fmt formats the given files or the files for the given packages in place
 `,
 		RunE: mkRunE(c, func(cmd *Command, args []string) error {
-			for _, inst := range load.Instances(args, nil) {
+			for _, inst := range load.Instances(args, &load.Config{
+				Tests: true,
+				Tools: true,
+			}) {
 				if inst.Err != nil {
 					exitOnErr(cmd, inst.Err, false)
 					continue