Add Mass.ShortTon abbreviation: "ST" (#760)

* Added "ST" as an abbreviation for short ton (common in nuclear industry to distinguish from metric tons)

* Regen code

Co-authored-by: Andreas Gullberg Larsen <[email protected]>

Author: trb5016

Common/UnitDefinitions/Mass.json

@@ -59,7 +59,7 @@
       "Localization": [
         {
           "Culture": "en-US",
-          "Abbreviations": [ "short tn" ]
+          "Abbreviations": [ "short tn", "ST" ]
         },
         {
           "Culture": "ru-RU",