[PT Run > Time and Date plugin] Custom formats and other improvements (#37743)

* add settings definition

* fix typos and improve settings

* make spell checker happy

* new icon type error

* first code to handle custom formats

* support parsing of new formats

* spelling and typos

* comment fix

* spell check

* start implement custom format results

* last changes

* finish implementation

* spell checker

* settings name

* add missing format

* reorder settings

* dev docs

* change ELF to EAB

* update dev docs

* last changes

* test cases

* fix typos

* fix typo

* port changes

* fixes

* changes

* fixes

* leap year support

* days in month

* tests

* comment

* fix comment

src/modules/launcher/Plugins/Microsoft.PowerToys.Run.Plugin.TimeDate/Components/AvailableResult.cs

@@ -7,7 +7,7 @@ using System.Runtime.CompilerServices;
 
 namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Components
 {
-    internal class AvailableResult
+    internal sealed class AvailableResult
     {
         /// <summary>
         /// Gets or sets the time/date value
@@ -41,6 +41,7 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Components
                 ResultIconType.Time => $"Images\\time.{theme}.png",
                 ResultIconType.Date => $"Images\\calendar.{theme}.png",
                 ResultIconType.DateTime => $"Images\\timeDate.{theme}.png",
+                ResultIconType.Error => $"Images\\Warning.{theme}.png",
                 _ => string.Empty,
             };
         }
@@ -51,5 +52,6 @@ namespace Microsoft.PowerToys.Run.Plugin.TimeDate.Components
         Time,
         Date,
         DateTime,
+        Error,
     }
 }