Add placeholder options for freeform keys

Models/ThemeConfig/Json/TagRenderingConfigJson.ts

@@ -56,6 +56,11 @@ export interface TagRenderingConfigJson {
          * See Docs/SpecialInputElements.md and UI/Input/ValidatedTextField.ts for supported values
          */
         type?: string,
+        /**
+         * A (translated) text that is shown (as gray text) within the textfield
+         */
+        placeholder: string | any
+        
         /**
          * Extra parameters to initialize the input helper arguments.
          * For semantics, see the 'SpecialInputElements.md'

Models/ThemeConfig/TagRenderingConfig.ts

@@ -30,6 +30,7 @@ export default class TagRenderingConfig {
     readonly freeform?: {
         readonly key: string,
         readonly type: string,
+        readonly placeholder: Translation,
         readonly addExtraTags: TagsFilter[];
         readonly inline: boolean,
         readonly default?: string,
@@ -93,6 +94,7 @@ export default class TagRenderingConfig {
             this.freeform = {
                 key: json.freeform.key,
                 type: json.freeform.type ?? "string",
+                placeholder: Translations.T(json.freeform.placeholder ?? (json.freeform.key + "(" + (json.freeform.type ?? "string") + ")")),
                 addExtraTags: json.freeform.addExtraTags?.map((tg, i) =>
                     TagUtils.Tag(tg, `${context}.extratag[${i}]`)) ?? [],
                 inline: json.freeform.inline ?? false,

UI/Popup/TagRenderingQuestion.ts

@@ -425,7 +425,8 @@ export default class TagRenderingQuestion extends Combine {
             mapBackgroundLayer: state.backgroundLayer,
             unit: applicableUnit,
             args: configuration.freeform.helperArgs,
-            feature: feature
+            feature: feature,
+            placeholder: configuration.freeform.placeholder
         });
 
         input.GetValue().setData(tagsData[freeform.key] ?? freeform.default);