Fixed typo (thanks @Akaricchi!)

include/SDL3/SDL_pixels.h

@@ -482,7 +482,7 @@ typedef enum
     SDL_TRANSFER_CHARACTERISTICS_PQ = 16,           /**< SMPTE ST 2084 for 10-, 12-, 14- and 16-bit systems */
     SDL_TRANSFER_CHARACTERISTICS_SMPTE428 = 17,     /**< SMPTE ST 428-1 */
     SDL_TRANSFER_CHARACTERISTICS_HLG = 18,          /**< ARIB STD-B67, known as "Hybrid log-gamma" */
-    SDL_TRANSFER_COEFFICIENTS_CUSTOM = 31
+    SDL_TRANSFER_CHARACTERISTICS_CUSTOM = 31
 } SDL_TransferCharacteristics;
 
 /**