[PTRun][UnitConverter]Add usage prompt

src/modules/launcher/Plugins/Community.PowerToys.Run.Plugin.UnitConverter/Main.cs

@@ -30,6 +30,8 @@ namespace Community.PowerToys.Run.Plugin.UnitConverter
         private bool _disposed;
 
         private static readonly CompositeFormat CopyToClipboard = System.Text.CompositeFormat.Parse(Properties.Resources.copy_to_clipboard);
+        private static readonly CompositeFormat UsagePromptTitle = System.Text.CompositeFormat.Parse(Properties.Resources.usage_prompt_title);
+        private static readonly CompositeFormat UsagePromptSubtitle = System.Text.CompositeFormat.Parse(Properties.Resources.usage_prompt_subtitle);
 
         public void Init(PluginInitContext context)
         {
@@ -44,6 +46,14 @@ namespace Community.PowerToys.Run.Plugin.UnitConverter
         {
             ArgumentNullException.ThrowIfNull(query);
 
+            bool isKeywordSearch = !string.IsNullOrEmpty(query.ActionKeyword);
+            bool isEmptySearch = string.IsNullOrEmpty(query.Search);
+
+            if (isEmptySearch && isKeywordSearch)
+            {
+                return GetSuggestionResults(query);
+            }
+
             // Parse
             ConvertModel convertModel = InputInterpreter.Parse(query);
             if (convertModel == null)
@@ -56,6 +66,24 @@ namespace Community.PowerToys.Run.Plugin.UnitConverter
                 .ToList();
         }
 
+        private List<Result> GetSuggestionResults(Query query)
+        {
+            var title = string.Format(CultureInfo.CurrentCulture, UsagePromptTitle, query.ActionKeyword);
+            var subTitle = string.Format(CultureInfo.CurrentCulture, UsagePromptSubtitle);
+            List<Result> ret =
+            [
+                new Result
+                {
+                    Title = title,
+                    SubTitle = subTitle,
+                    IcoPath = _icon_path,
+                    Action = c => true,
+                }
+            ];
+
+            return ret;
+        }
+
         private Result GetResult(UnitConversionResult result)
         {
             return new Result

src/modules/launcher/Plugins/Community.PowerToys.Run.Plugin.UnitConverter/Properties/Resources.Designer.cs

@@ -104,5 +104,23 @@ namespace Community.PowerToys.Run.Plugin.UnitConverter.Properties {
                 return ResourceManager.GetString("plugin_name", resourceCulture);
             }
         }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to e.g. 10 ft to m.
+        /// </summary>
+        public static string usage_prompt_subtitle {
+            get {
+                return ResourceManager.GetString("usage_prompt_subtitle", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Usage: {0} [value] [fromUnit] to [toUnit].
+        /// </summary>
+        public static string usage_prompt_title {
+            get {
+                return ResourceManager.GetString("usage_prompt_title", resourceCulture);
+            }
+        }
     }
 }

src/modules/launcher/Plugins/Community.PowerToys.Run.Plugin.UnitConverter/Properties/Resources.resx

@@ -132,4 +132,10 @@
   <data name="plugin_name" xml:space="preserve">
     <value>Unit Converter</value>
   </data>
+  <data name="usage_prompt_subtitle" xml:space="preserve">
+    <value>e.g. 10 ft to m</value>
+  </data>
+  <data name="usage_prompt_title" xml:space="preserve">
+    <value>Usage: {0} [value] [fromUnit] to [toUnit]</value>
+  </data>
 </root>