Add singular forms for units

Models/ThemeConfig/Json/UnitConfigJson.ts

@@ -24,7 +24,12 @@ export interface ApplicableUnitJson
      * If the user inputs '42', the canonical value will be added and it'll become '42m'
      */
     canonicalDenomination: string,
-
+    /**
+     * The canonical denomination in the case that the unit is precisely '1'
+     */
+    canonicalDenominationSingular?: string,
+    
+    
     /**
      * A list of alternative values which can occur in the OSM database - used for parsing.
      */
@@ -39,6 +44,15 @@ export interface ApplicableUnitJson
      */
     human?: string | any
 
+    /**
+     * The value for humans in the dropdown. This should not use abbreviations and should be translated, e.g.
+     * {
+     *     "en": "minute",
+     *     "nl": "minuut"x²
+     * }
+     */
+    humanSingular?: string | any
+
     /**
      * If set, then the canonical value will be prefixed instead, e.g. for '€'
      * Note that if all values use 'prefix', the dropdown might move to before the text field