Send Ctrl+Enter

Hi

I'm having problems sending messages in telegram.
When I use physical keyboard, Ctrl+Enter works fine.

But when I try to send Ctrl+Enter via adbkeyboard it simply does not work:
```
$ adb shell am broadcast -a ADB_INPUT_MCODE --eia mcode '4096,66'
```

Would it be possible to add example with Ctrl+Enter to README.md?

Much appreciated