fix typo in nozzle cleaning

typo introduced in 76ea342

Author: Frix-x

macros/helpers/nozzle_cleaning.cfg

@@ -120,8 +120,8 @@ gcode:
 
         # Retract
         G92 E0
-        G1 E-{RETRACT*0.1} F2100
-        G1 E-({RETRACT}-{RETRACT*0.1}) F150
+        G1 E-{RETRACT * 0.1} F2100
+        G1 E-{RETRACT - (RETRACT * 0.1)} F150
         G92 E0
 
         # Wait some time to let the nozzle ooze before cleaning
@@ -173,4 +173,4 @@ gcode:
         {% endif %}
 
         RESTORE_GCODE_STATE NAME=CONDITIONAL_MOVE_TO_PURGE_BUCKET_STATE
-    {% endif %}
+    {% endif %}