Group element helpers in different files (#21)

According to the section at https://developer.mozilla.org/en-US/docs/Web/HTML/Element

1 files changed, 16 insertions, 0 deletions

diff --git a/attr/form_test.go b/attr/form_test.go
new file mode 100644
index 0000000..d222464
--- /dev/null
+++ b/attr/form_test.go
@@ -0,0 +1,16 @@
+package attr_test
+
+import (
+	"testing"
+
+	g "github.com/maragudk/gomponents"
+	"github.com/maragudk/gomponents/assert"
+	"github.com/maragudk/gomponents/attr"
+)
+
+func TestForms(t *testing.T) {
+	t.Run("adds placeholder and required attributes", func(t *testing.T) {
+		e := g.El("input", attr.Placeholder("hat"), attr.Required())
+		assert.Equal(t, `<input placeholder="hat" required />`, e)
+	})
+}