[Docs] Make Code Examples Consistent On Combo Page (#6078)

docs/feature_combo.md

@@ -29,6 +29,7 @@ enum combos {
   AB_ESC,
   JK_TAB
 };
+
 const uint16_t PROGMEM ab_combo[] = {KC_A, KC_B, COMBO_END};
 const uint16_t PROGMEM jk_combo[] = {KC_J, KC_K, COMBO_END};