Added documentation for Serial Protocol HoTT Telemetry

[mha1]

new in 3.4

[mha1]

@deadbytefpv can I do anything about the spell check fail?

[deadbytefpv]

@deadbytefpv can I do anything about the spell check fail?

you can add words into the accepted word list found here: https://github.com/ExpressLRS/Docs/blob/master/.wordlist.txt

but it's @maybenikhil who knows it better. o