update readme and contributors for renesas rx63n and silabs efm32gg12 port (#767)

* update readme and contributors for renesas rx63n and silabs efm32gg12 port

also add some doc for changelog

* typo

* update more boards

* more typo

* typo 3

CONTRIBUTORS.md

@@ -33,6 +33,7 @@
 
 - **[Koji KITAYAMA](https://github.com/kkitayam)**
   - Add new DCD port for **NXP Kinetis KL25**
+  - Add new DCD port for **Renesas RX63n** with GR-CITRUS board
 
 - **[Nathan Conrad](https://github.com/pigrew)**
   - Add new DCD port for **STM32 fsdev** Fullspeed device for STM32 L0, F0, F1, F3 etc ...
@@ -47,6 +48,9 @@
   - Board support for NuTiny NUC120, NUC121s, NUC125s, NUC126V, NUC505
   - Improve multiple cdc interfaces API & add cdc_dual_ports example
 
+- **[Rafael Silva](https://github.com/perigoso)**
+  - Add new DCD port for **Silabs EFM32GG12** with SLTB009A board
+
 - **[Raspberry Pi Team](https://github.com/raspberrypi)**
   - Add new DCD port for **Raspberry Pi RP2040**
 
@@ -59,7 +63,7 @@
   - Add new class driver for **Musical Instrument Digital Interface (MIDI)**
   - Improve USBD control transfer, MSC, CDC class driver
   - Board support for Metro M0 & M4 express
-  - Write the execellent porting.md documentation
+  - Write the excellent porting.md documentation
   - Add initial Makefile
 
 - **[Sean Cross](https://github.com/xobs)**