Add RC-specific 0xEE sync byte

[akumaigorodski]

Radiomaster controllers (TX12, TX16 models at least with EdgeTX v2.8.0-2.9.1) use 0xEE as RcChannelsPacked sync byte, but 0xCE for other types of messages, this makes parser to search for either of these two bytes to successfully parse all the messages.

[tact1m4n3]

Hi! Thanks for your PR. However I am not sure that changing the Default implementation of the config struct is worth it in this case. To achieve the same effect, you can pass a custom config struct to the parser. On the other hand, I think that silently skipping bytes when we encounter an unrecognized sync byte (where we expect a packet to start) might not be the best way to tackle the situation. So as an alternative, I suggest we make a new parser error for this (InvalidSyncByte) and for the times we actually want to sync (search for the beginning of a packet) we can make a new method. This would at least give a heads up to the programmer that something is wrong.

[akumaigorodski]

Well, I did it this exact way because there's specific instruction about it here: https://github.com/crsf-wg/crsf/wiki/Message-Format#sync

But I can do it as an error, too. In that case I would probably want that error to contain raw packet bytes, because what I work on is a proxy program which takes CRSF stream from RF module's UART, looks for interesting bits, and then sends it to flight controller UART anyway, so such RC data can't be discarded.

[tact1m4n3]

Well, I did it this exact way because there's specific instruction about it here: https://github.com/crsf-wg/crsf/wiki/Message-Format#sync

Sounds good then :)) I'll merge the PR.

[tact1m4n3]

But I can do it as an error, too. In that case I would probably want that error to contain raw packet bytes, because what I work on is a proxy program which takes CRSF stream from RF module's UART, looks for interesting bits, and then sends it to flight controller UART anyway, so such RC data can't be discarded.

I'll probably add some sort of error for this anyway in the future.
On second thought I don't think an error is a good idea :)) I'd rather have the parser automatically sync to the first valid packet.

[tact1m4n3]

Thank you so much for your contribution!