move gotd fork into repo. (#111)

- update to latest telegram layer
- remove some references to fields in tg.Entities that don't exist in
the schema
- originally added here:
https://github.com/beeper/td/commit/820929062a2ba0104397bc01235ab58a9cff780e
  - referenced here
-
https://github.com/mautrix/telegramgo/commit/124f0967ed195b5a380c9bd02e170ada9710dde3
-
https://github.com/mautrix/telegramgo/commit/4205047aab2e0639217148b5d125bfaab668bd8e

pkg/gotd/telegram/message/entity/write_test.go

@@ -0,0 +1,55 @@
+package entity
+
+import (
+	"encoding/hex"
+	"testing"
+	"unicode/utf8"
+
+	"github.com/stretchr/testify/require"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/testutil"
+)
+
+func TestComputeLength(t *testing.T) {
+	tests := []struct {
+		s    string
+		want int
+	}{
+		{string([]rune{97, 127987, 65039, 8205, 127752}), 7},
+		{string([]int32{97, 127987, 65039, 8205, 127752, 127987, 65039, 8205, 127752}), 13},
+		{string([]int32{97, 128104, 8205, 128102, 8205, 128102}), 9},
+	}
+	for _, tt := range tests {
+		r := []byte(tt.s)
+		testutil.ZeroAlloc(t, func() {
+			_ = ComputeLength(tt.s)
+		})
+		testutil.ZeroAlloc(t, func() {
+			_ = ComputeLengthBytes(r)
+		})
+		t.Run(hex.EncodeToString([]byte(tt.s)), func(t *testing.T) {
+			require.Equal(t, tt.want, ComputeLength(tt.s))
+			require.Equal(t, tt.want, ComputeLengthBytes(r))
+		})
+	}
+}
+
+func TestBuilder_Write(t *testing.T) {
+	var (
+		a = require.New(t)
+		b Builder
+	)
+	_, err := b.Write([]byte("abc"))
+	a.NoError(err)
+	_, err = b.WriteString("abc")
+	a.NoError(err)
+	a.NoError(b.WriteByte('\n'))
+	a.Equal(3+3+1, b.UTF8Len())
+	a.Equal(3+3+1, b.UTF16Len())
+
+	var r rune = 127987
+	_, err = b.WriteRune(r)
+	a.NoError(err)
+	a.Equal(3+3+1+utf8.RuneLen(r), b.UTF8Len())
+	a.Equal(3+3+1+utf16RuneLen(r), b.UTF16Len())
+}