Refactor new API Symbols.

Author: KlausLoeffelmann

src/System.Windows.Forms/System/Windows/Forms/Form.cs

@@ -2655,7 +2655,6 @@ public event FormClosingEventHandler? FormClosing
     /// </summary>
     [SRCategory(nameof(SR.CatAppearance))]
     [SRDescription(nameof(SR.FormBorderColorChangedDescr))]
-    [Experimental(DiagnosticIDs.ExperimentalDarkMode, UrlFormat = DiagnosticIDs.UrlFormat)]
     public event EventHandler? FormBorderColorChanged
     {
         add => Events.AddHandler(s_formBorderColorChanged, value);
@@ -2667,7 +2666,6 @@ public event EventHandler? FormBorderColorChanged
     /// </summary>
     [SRCategory(nameof(SR.CatAppearance))]
     [SRDescription(nameof(SR.FormCaptionBackColorChangedDescr))]
-    [Experimental(DiagnosticIDs.ExperimentalDarkMode, UrlFormat = DiagnosticIDs.UrlFormat)]
     public event EventHandler? FormCaptionBackColorChanged
     {
         add => Events.AddHandler(s_formCaptionBackColorChanged, value);
@@ -2679,7 +2677,6 @@ public event EventHandler? FormCaptionBackColorChanged
     /// </summary>
     [SRCategory(nameof(SR.CatAppearance))]
     [SRDescription(nameof(SR.FormCaptionTextColorChangedDescr))]
-    [Experimental(DiagnosticIDs.ExperimentalDarkMode, UrlFormat = DiagnosticIDs.UrlFormat)]
     public event EventHandler? FormCaptionTextColorChanged
     {
         add => Events.AddHandler(s_formCaptionTextColorChanged, value);
@@ -2691,7 +2688,6 @@ public event EventHandler? FormCaptionTextColorChanged
     /// </summary>
     [SRCategory(nameof(SR.CatAppearance))]
     [SRDescription(nameof(SR.FormCornerPreferenceChangedDescr))]
-    [Experimental(DiagnosticIDs.ExperimentalDarkMode, UrlFormat = DiagnosticIDs.UrlFormat)]
     public event EventHandler? FormCornerPreferenceChanged
     {
         add => Events.AddHandler(s_formCornerPreferenceChanged, value);
@@ -4198,12 +4194,10 @@ protected override void OnHandleCreated(EventArgs e)
             SetFormAttributeColorInternal(DWMWINDOWATTRIBUTE.DWMWA_TEXT_COLOR, formCaptionTextColor.Value);
         }
 
-#pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
         if (Properties.TryGetValue(s_propFormCornerPreference, out FormCornerPreference? cornerPreference))
         {
             SetFormCornerPreferenceInternal(cornerPreference.Value);
         }
-#pragma warning restore WFO5001
 
         UpdateLayered();
 
@@ -4959,7 +4953,6 @@ internal override unsafe void RecreateHandleCore()
             Debug.Assert(result);
         }
 
-#pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
         if (TopLevel && IsHandleCreated)
         {
             FormCornerPreference formCornerPreference = Properties.GetValueOrDefault(s_propFormCornerPreference, FormCornerPreference.Default);
@@ -4974,7 +4967,6 @@ internal override unsafe void RecreateHandleCore()
             colorValue = Properties.GetValueOrDefault(s_propFormBorderColor, Color.Empty);
             SetFormAttributeColorInternal(DWMWINDOWATTRIBUTE.DWMWA_BORDER_COLOR, colorValue);
         }
-#pragma warning restore WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
 
         GC.KeepAlive(this);
     }