add tag values as part of the label

addresses #447 (comment)

Author: tyrasd

data/fields/transformer.json

@@ -4,12 +4,12 @@
     "label": "Type",
     "strings": {
         "options": {
-            "main": "Forwards power",
-            "distribution": "Feeds final consumers, installed outside substations",
-            "generator": "Steps-up voltage in power plants",
-            "converter": "Feeds power converters",
+            "main": "Main: Forwards power",
+            "distribution": "Distribution: Feeds final consumers, installed outside substations",
+            "generator": "Generator: Steps-up voltage in power plants",
+            "converter": "Converter: Feeds power converters",
             "phase_angle_regulator": "Regulates phase angle",
-            "auxiliary": "Feeds internal systems in substations",
+            "auxiliary": "Auxiliary: Feeds internal systems in substations",
             "yes": "Unknown role"
         }
     },

interim/source_strings.yaml

@@ -3348,15 +3348,15 @@ en:
         label: Type
         options:
           # transformer=auxiliary
-          auxiliary: Feeds internal systems in substations
+          auxiliary: 'Auxiliary: Feeds internal systems in substations'
           # transformer=converter
-          converter: Feeds power converters
+          converter: 'Converter: Feeds power converters'
           # transformer=distribution
-          distribution: Feeds final consumers, installed outside substations
+          distribution: 'Distribution: Feeds final consumers, installed outside substations'
           # transformer=generator
-          generator: Steps-up voltage in power plants
+          generator: 'Generator: Steps-up voltage in power plants'
           # transformer=main
-          main: Forwards power
+          main: 'Main: Forwards power'
           # transformer=phase_angle_regulator
           phase_angle_regulator: Regulates phase angle
           # transformer=yes