Implement HTML writer (#33)

Reviewed-on: #33
Co-authored-by: Natercio Moniz <[email protected]>

internal/writing/localizer_test.go

@@ -0,0 +1,28 @@
+package writing_test
+
+import (
+	"testing"
+
+	"github.com/nmoniz/any2anexoj/internal/writing"
+)
+
+func TestNewLocalizer(t *testing.T) {
+	tests := []struct {
+		name string
+		lang string
+	}{
+		{"english", "en"},
+		{"portuguese", "pt"},
+		{"english with region", "en-US"},
+		{"portuguese with region", "pt-BR"},
+		{"unknown language falls back to default", "!!"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			_, err := writing.NewLocalizer(tt.lang)
+			if err != nil {
+				t.Fatalf("want success call but failed: %v", err)
+			}
+		})
+	}
+}