[Docs] Clean up some code block languages (#14434)

docs/feature_rawhid.md

@@ -15,7 +15,7 @@ RAW_ENABLE = yes
 
 In your `keymap.c` include `"raw_hid.h"` and implement the following:
 
-```C
+```c
 void raw_hid_receive(uint8_t *data, uint8_t length) {
     // Your code goes here. data is the packet received from host.
 }
@@ -23,7 +23,7 @@ void raw_hid_receive(uint8_t *data, uint8_t length) {
 
 The `"raw_hid.h"` header also declares `void raw_hid_send(uint8_t *data, uint8_t length);` which allows sending packets from keyboard to host. As an example, it can also be used for debugging when building your host application by returning all data back to the host.
 
-```C
+```c
 void raw_hid_receive(uint8_t *data, uint8_t length) {
     raw_hid_send(data, length);
 }