Tweak some feedrate vars

Marlin/Marlin.h

 #if ENABLED(FWRETRACT)
   extern bool autoretract_enabled;
   extern bool retracted[EXTRUDERS]; // extruder[n].retracted
-  extern float retract_length, retract_length_swap, retract_feedrate, retract_zlift;
+  extern float retract_length, retract_length_swap, retract_feedrate_mm_s, retract_zlift;
   extern float retract_recover_length, retract_recover_length_swap, retract_recover_feedrate;
 #endif
 

Marlin/Marlin_main.cpp

 
   float retract_length = RETRACT_LENGTH;
   float retract_length_swap = RETRACT_LENGTH_SWAP;
-  float retract_feedrate = RETRACT_FEEDRATE;
+  float retract_feedrate_mm_s = RETRACT_FEEDRATE;
   float retract_zlift = RETRACT_ZLIFT;
   float retract_recover_length = RETRACT_RECOVER_LENGTH;
   float retract_recover_length_swap = RETRACT_RECOVER_LENGTH_SWAP;
 
     if (retracting == retracted[active_extruder]) return;
 
-    float oldFeedrate = feedrate;
+    float old_feedrate = feedrate;
 
     set_destination_to_current();
 
     if (retracting) {
 
-      feedrate = retract_feedrate * 60;
+      feedrate = retract_feedrate_mm_s * 60;
       current_position[E_AXIS] += (swapping ? retract_length_swap : retract_length) / volumetric_multiplier[active_extruder];
       sync_plan_position_e();
       prepare_move_to_destination();
       prepare_move_to_destination();
     }
 
-    feedrate = oldFeedrate;
+    feedrate = old_feedrate;
     retracted[active_extruder] = retracting;
 
   } // retract()
    *
    *   S[+mm]    retract_length
    *   W[+mm]    retract_length_swap (multi-extruder)
-   *   F[mm/min] retract_feedrate
+   *   F[mm/min] retract_feedrate_mm_s
    *   Z[mm]     retract_zlift
    */
   inline void gcode_M207() {
     if (code_seen('S')) retract_length = code_value_axis_units(E_AXIS);
-    if (code_seen('F')) retract_feedrate = code_value_axis_units(E_AXIS) / 60;
+    if (code_seen('F')) retract_feedrate_mm_s = code_value_axis_units(E_AXIS) / 60;
     if (code_seen('Z')) retract_zlift = code_value_axis_units(Z_AXIS);
     #if EXTRUDERS > 1
       if (code_seen('W')) retract_length_swap = code_value_axis_units(E_AXIS);

Marlin/configuration_store.cpp

  *  391  M209 S    autoretract_enabled (bool)
  *  392  M207 S    retract_length (float)
  *  396  M207 W    retract_length_swap (float)
- *  400  M207 F    retract_feedrate (float)
+ *  400  M207 F    retract_feedrate_mm_s (float)
  *  404  M207 Z    retract_zlift (float)
  *  408  M208 S    retract_recover_length (float)
  *  412  M208 W    retract_recover_length_swap (float)
       dummy = 0.0f;
       EEPROM_WRITE_VAR(i, dummy);
     #endif
-    EEPROM_WRITE_VAR(i, retract_feedrate);
+    EEPROM_WRITE_VAR(i, retract_feedrate_mm_s);
     EEPROM_WRITE_VAR(i, retract_zlift);
     EEPROM_WRITE_VAR(i, retract_recover_length);
     #if EXTRUDERS > 1
       #else
         EEPROM_READ_VAR(i, dummy);
       #endif
-      EEPROM_READ_VAR(i, retract_feedrate);
+      EEPROM_READ_VAR(i, retract_feedrate_mm_s);
       EEPROM_READ_VAR(i, retract_zlift);
       EEPROM_READ_VAR(i, retract_recover_length);
       #if EXTRUDERS > 1
     #if EXTRUDERS > 1
       retract_length_swap = RETRACT_LENGTH_SWAP;
     #endif
-    retract_feedrate = RETRACT_FEEDRATE;
+    retract_feedrate_mm_s = RETRACT_FEEDRATE;
     retract_zlift = RETRACT_ZLIFT;
     retract_recover_length = RETRACT_RECOVER_LENGTH;
     #if EXTRUDERS > 1
     #if EXTRUDERS > 1
       SERIAL_ECHOPAIR(" W", retract_length_swap);
     #endif
-    SERIAL_ECHOPAIR(" F", retract_feedrate * 60);
+    SERIAL_ECHOPAIR(" F", retract_feedrate_mm_s * 60);
     SERIAL_ECHOPAIR(" Z", retract_zlift);
     SERIAL_EOL;
     CONFIG_ECHO_START;

Marlin/ultralcd.cpp

       #if EXTRUDERS > 1
         MENU_ITEM_EDIT(float52, MSG_CONTROL_RETRACT_SWAP, &retract_length_swap, 0, 100);
       #endif
-      MENU_ITEM_EDIT(float3, MSG_CONTROL_RETRACTF, &retract_feedrate, 1, 999);
+      MENU_ITEM_EDIT(float3, MSG_CONTROL_RETRACTF, &retract_feedrate_mm_s, 1, 999);
       MENU_ITEM_EDIT(float52, MSG_CONTROL_RETRACT_ZLIFT, &retract_zlift, 0, 999);
       MENU_ITEM_EDIT(float52, MSG_CONTROL_RETRACT_RECOVER, &retract_recover_length, 0, 100);
       #if EXTRUDERS > 1