locale: made "weight_unit:ton" translatable, required for French.

shared/translations/en-us.json

@@ -6427,5 +6427,9 @@
     {
         "term": "speed_limit_property:no_limit",
         "definition": "No limit"
+    },
+    {
+        "term": "weight_unit:ton",
+        "definition": "ton"
     }
 ]

shared/translations/neutral.json

@@ -279,10 +279,6 @@
         "term": "weight_unit:short_tons",
         "definition": "Short tons"
     },
-    {
-        "term": "weight_unit:ton",
-        "definition": "ton"
-    },
     {
         "term": "world_scale:h0",
         "definition": "H0 (1:87)"
@@ -391,4 +387,4 @@
         "term": "loconet_command_station:uhlenbrock_intellibox_2",
         "definition": "Uhlenbrock Intellibox II"
     }
-]
+]