Fix axis name in serial output (#18522)

Marlin/src/core/types.h

 #undef FI
 
 const xyze_char_t axis_codes { 'X', 'Y', 'Z', 'E' };
-#define XYZ_CHAR(A) ('X' + char(A))
+#define XYZ_CHAR(A) ((char)('X' + A))