Follow-up the PR #3676(Advance extrusion algorithm – LIN_ADVANCE)

・Update forgotten example configurations

Marlin/example_configurations/SCARA/Configuration_adv.h

@@ -445,6 +445,15 @@
   #define D_FILAMENT 1.75
 #endif
 
+// Implementation of a linear pressure control
+// Assumption: advance = k * (delta velocity)
+// K=0 means advance disabled. A good value for a gregs wade extruder will be around K=75
+//#define LIN_ADVANCE
+
+#if ENABLED(LIN_ADVANCE)
+  #define LIN_ADVANCE_K 75
+#endif
+
 // @section leveling
 
 // Default mesh area is an area with an inset margin on the print area.