Fix plural form for galaxies

constants.js

@@ -136,7 +136,7 @@ const buildings = {
   },
   "galaxy": {
     "name": "Galaxy",
-    "plural": "Galaxy",
+    "plural": "Galaxies",
     "desc": "In a galaxy far, far down your gullet...",
     "cost": 4.0e17,
     "prod": 1e15/2.6,