Slightly Slower Max X Axis speed

On some T-Rex 2+ machines the previous max step rate could lose steps....

Marlin/src/config/examples/Formbot/T_Rex_2+/Configuration.h

  * Override with M203
  *                                      X, Y, Z, E0 [, E1[, E2[, E3[, E4[, E5]]]]]
  */
-#define DEFAULT_MAX_FEEDRATE          { 250, 100, 5, 25 }
+#define DEFAULT_MAX_FEEDRATE          { 200, 100, 5, 25 }
 
 /**
  * Default Max Acceleration (change/s) change = mm/s