all: Minor cleanups

if x { return true } return false => return x

	fmt.Sprintf("%v", x) => fmt.Sprint(x) or x.String()

The fmt.Sprintf idiom is still used in the SecretString tests, where it
serves security hardening.

internal/cache/file_test.go

@@ -97,7 +97,7 @@ func TestFiles(t *testing.T) {
 	}
 
 	for _, tpe := range tests {
-		t.Run(fmt.Sprintf("%v", tpe), func(t *testing.T) {
+		t.Run(tpe.String(), func(t *testing.T) {
 			ids := generateRandomFiles(t, tpe, c)
 			id := randomID(ids)