doc: release-notes: add notes for LoRa, LoRaWAN and LED

Add release notes for LoRa, LoRaWAN and LED, got these from Manivannan
on Discord.

Signed-off-by: Fabio Baltieri <[email protected]>
Co-authored-by: Manivannan Sadhasivam <[email protected]>

Author: fabiobaltieri

doc/releases/release-notes-3.2.rst

@@ -595,10 +595,18 @@ Drivers and Sensors
 
 * LED
 
-  * Updated LED PWM support for ESP32 boards
+  * Added support for using multiple instances of LP5562 LED module.
+  * Devicetree usage cleanups.
+  * i2c_dt_spec migration.
+  * Updated LED PWM support for ESP32 boards.
 
 * LoRa
 
+  * Added support for setting the sync-word and iq-inverted modes in LoRa modems.
+  * Removed ``REQUIRES_FULL_LIBC`` library dependency from LoRa drivers. This
+    results in considerable flash memory savings.
+  * Devicetree usage cleanups.
+
 * MBOX
 
 * MEMC
@@ -1382,6 +1390,11 @@ Libraries / Subsystems
 
 * LoRaWAN
 
+  * Added Class-C support.
+  * Upgraded the loramac-node repository to v4.6.0.
+  * Moved the ``REQUIRES_FULL_LIBC`` library dependency from LoRa to LoRaWAN.
+  * Fixed the async reception in SX127x modems.
+
 * Modbus
 
 * Power management