Enhance the style of the checkboxes for multi-selection (#1244)

* Enhance the checkboxes' style for multi-selection by applying the selected style, if available, to the checkboxes currently selected.

src/Spectre.Console/Prompts/List/ListPromptConstants.cs

@@ -9,4 +9,15 @@ internal sealed class ListPromptConstants
     public const string InstructionsMarkup = "[grey](Press <space> to select, <enter> to accept)[/]";
     public const string MoreChoicesMarkup = "[grey](Move up and down to reveal more choices)[/]";
     public const string SearchPlaceholderMarkup = "[grey](Type to search)[/]";
+
+    public static string GetSelectedCheckbox(bool isGroup, SelectionMode mode, Style? style = null)
+    {
+        if (style != null)
+        {
+            return "[[" + $"[{style.ToMarkup()}]X[/]" + "]]";
+        }
+
+        return isGroup && mode == SelectionMode.Leaf
+            ? GroupSelectedCheckbox : SelectedCheckbox;
+    }
 }

src/Spectre.Console/Prompts/MultiSelectionPrompt.cs

@@ -257,8 +257,7 @@ public sealed class MultiSelectionPrompt<T> : IPrompt<List<T>>, IListPromptStrat
             }
 
             var checkbox = item.Node.IsSelected
-                ? (item.Node.IsGroup && Mode == SelectionMode.Leaf
+                ? ListPromptConstants.GetSelectedCheckbox(item.Node.IsGroup, Mode, HighlightStyle)
-                    ? ListPromptConstants.GroupSelectedCheckbox : ListPromptConstants.SelectedCheckbox)
                 : ListPromptConstants.Checkbox;
 
             grid.AddRow(new Markup(indent + prompt + " " + checkbox + " " + text, style));

src/Spectre.Console/Widgets/Calendar.cs

@@ -195,7 +195,7 @@ public sealed class Calendar : JustInTimeRenderable, IHasCulture, IHasTableBorde
         while (currentDay <= daysInMonth)
         {
             if (weekdays[currentDay - 1] == weekday)
-            {
+            {
                 var todayEvent = _calendarEvents.LastOrDefault(e => e.Month == Month && e.Day == currentDay);
                 if (todayEvent != null)
                 {

src/Spectre.Console/Widgets/CalendarEvent.cs

@@ -28,34 +28,34 @@ public sealed class CalendarEvent
     /// <summary>
     /// Gets the custom highlight style of the calendar event.
     /// </summary>
-    public Style? CustomHighlightStyle { get; }
+    public Style? CustomHighlightStyle { get; }
-
+
     /// <summary>
     /// Initializes a new instance of the <see cref="CalendarEvent"/> class.
     /// </summary>
     /// <param name="year">The year of the calendar event.</param>
     /// <param name="month">The month of the calendar event.</param>
-    /// <param name="day">The day of the calendar event.</param>
+    /// <param name="day">The day of the calendar event.</param>
     /// <param name="customHighlightStyle">The custom highlight style of the calendar event.</param>
     public CalendarEvent(int year, int month, int day, Style? customHighlightStyle = null)
         : this(string.Empty, year, month, day, customHighlightStyle)
     {
-    }
+    }
-
+
     /// <summary>
     /// Initializes a new instance of the <see cref="CalendarEvent"/> class.
     /// </summary>
     /// <param name="description">The calendar event description.</param>
     /// <param name="year">The year of the calendar event.</param>
     /// <param name="month">The month of the calendar event.</param>
-    /// <param name="day">The day of the calendar event.</param>
+    /// <param name="day">The day of the calendar event.</param>
     /// <param name="customHighlightStyle">The custom highlight style of the calendar event.</param>
     public CalendarEvent(string description, int year, int month, int day, Style? customHighlightStyle = null)
     {
         Description = description ?? string.Empty;
         Year = year;
         Month = month;
-        Day = day;
+        Day = day;
         CustomHighlightStyle = customHighlightStyle;
     }
 }