Add IsKeyPressedRepeat (desktop only) (#3245)

Since the key pressed are handle by comparing current vs previous
state (ie frame), a special way is needed to handle key repeats.

src/raylib.h

@@ -1115,6 +1115,7 @@ RLAPI unsigned char *DecodeDataBase64(const unsigned char *data, int *outputSize
 
 // Input-related functions: keyboard
 RLAPI bool IsKeyPressed(int key);                             // Check if a key has been pressed once
+RLAPI bool IsKeyPressedRepeat(int key);                       // Check if a key has been pressed again (Only PLATFORM_DESKTOP)
 RLAPI bool IsKeyDown(int key);                                // Check if a key is being pressed
 RLAPI bool IsKeyReleased(int key);                            // Check if a key has been released once
 RLAPI bool IsKeyUp(int key);                                  // Check if a key is NOT being pressed