fix: false positives on structs

[letmein]

Ignore structs which are not being used as test tables.

For example, here "1" and "2" are reported as test examples:

func TestStruct(t *testing.T) {
	type item struct {
		id   string
		name string
	}
	items := []item{
		{"1", "one"},
		{"2", "two"},
	}

	for _, i := range items {
		if i.id == "" {
			t.Fail()
		}
	}
}

Before

After

[fredrikaverpil]

Hey @letmein and many thanks for this fix! ⭐