Fix prime tower purge description text

CURA-3094

resources/definitions/fdmprinter.def.json

@@ -4427,7 +4427,7 @@
                 "prime_tower_purge_volume":
                 {
                     "label": "Prime Tower Purge Volume",
-                    "description": "Amount of filament to be purged when wiping on prime tower. Purging is useful for compensating the filament lost by oozing during the inactivity of the nozzle.",
+                    "description": "Amount of filament to be purged when wiping on the prime tower. Purging is useful for compensating the filament lost by oozing during inactivity of the nozzle.",
                     "type": "float",
                     "enabled": "dual_pre_wipe",
                     "unit": "mm³",