added FLRC definition to glossary (#450)

Not sure if the definition is too technical or not, you can let me know.

Author: mu1q

docs/info/glossary.md

@@ -22,5 +22,6 @@ Below you can find a list of terms you might not be sure about, as well as some
 - `RSSI`: Received Signal Strength Indicator, "arbitrary" scaled version of `RSSI dBm` or LQ. [Signal Health: LQI and RSSI Explained](../info/signal-health.md)
 - `RSSI dBm`: Measure of power level measured in dBm. Basically, how strong the signal being received is
 - `S.Port`: SmartPort, sometimes referred to as `sport`. FrSky "telemetry" protocol. The `S.Port` also gets used for updating FrSky receivers.
+- `FLRC`: Fast Long Range Communication, also known as F-mode. It is a term that combines a few signal processing techniques (demodulation, forwarding error correction and interleaving) to enable high data rates. This results in lower latency and comparable (or shorter) range.
 
-To be continued.
+To be continued.