lsf: Add 'm' format specifier to show the MimeType

fs/operations/operations_test.go

@@ -716,6 +716,11 @@ func TestListFormat(t *testing.T) {
 	list.AddID()
 	_ = operations.ListFormatted(&items[0], &list) // Can't really check anything - at least it didn't panic!
 
+	list.SetOutput(nil)
+	list.AddMimeType()
+	assert.Contains(t, operations.ListFormatted(&items[0], &list), "/")
+	assert.Equal(t, "inode/directory", operations.ListFormatted(&items[1], &list))
+
 	list.SetOutput(nil)
 	list.AddSize()
 	assert.Equal(t, "1", operations.ListFormatted(&items[0], &list))