Fix bad links

[gewarren]

No description provided.

[Copilot]

Pull request overview

This PR updates .NET reference XML documentation to fix broken or outdated cross-links (primarily WPF and threading article URLs) and cleans up a few markdown formatting issues in remarks/examples blocks.

Changes:

• Replaced many outdated WPF doc links (for example, XAML Resources, Styling and Templating, and control “styles and templates” anchors).
• Updated .NET threading article links to newer slugs (for example, synchronization primitives, mutexes, semaphores, and reader-writer locks).
• Minor markdown formatting tweaks (spacing, line breaks, and example/remarks layout).

Reviewed changes

Copilot reviewed 80 out of 81 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
xml/System/FlagsAttribute.xml	Markdown spacing tweak in Examples text.
xml/System/Action.xml	NOTE block formatting cleanup.
xml/System.Windows.Media/VisualBrush.xml	Update XAML Resources link.
xml/System.Windows.Media/VectorCollection.xml	Update XAML Resources link.
xml/System.Windows.Media/TranslateTransform.xml	Update XAML Resources link.
xml/System.Windows.Media/TransformGroup.xml	Update XAML Resources link.
xml/System.Windows.Media/TransformCollection.xml	Update XAML Resources link.
xml/System.Windows.Media/SolidColorBrush.xml	Update XAML Resources link.
xml/System.Windows.Media/SkewTransform.xml	Update XAML Resources link.
xml/System.Windows.Media/ScaleTransform.xml	Update XAML Resources link.
xml/System.Windows.Media/RotateTransform.xml	Update XAML Resources link.
xml/System.Windows.Media/RadialGradientBrush.xml	Update XAML Resources link.
xml/System.Windows.Media/QuadraticBezierSegment.xml	Update XAML Resources link.
xml/System.Windows.Media/PointCollection.xml	Update XAML Resources link.
xml/System.Windows.Media/PathSegmentCollection.xml	Update XAML Resources link.
xml/System.Windows.Media/PathSegment.xml	Update XAML Resources link.
xml/System.Windows.Media/PathFigureCollection.xml	Update XAML Resources link.
xml/System.Windows.Media/LineSegment.xml	Update XAML Resources link.
xml/System.Windows.Media/LineGeometry.xml	Update XAML Resources link.
xml/System.Windows.Media/Int32Collection.xml	Update XAML Resources link.
xml/System.Windows.Media/ImageBrush.xml	Update XAML Resources link.
xml/System.Windows.Media/GradientStopCollection.xml	Update XAML Resources link.
xml/System.Windows.Media/Geometry.xml	Update XAML Resources link.
xml/System.Windows.Media/DrawingGroup.xml	Update XAML Resources link.
xml/System.Windows.Media/DrawingCollection.xml	Update XAML Resources link.
xml/System.Windows.Media/Drawing.xml	Update XAML Resources link.
xml/System.Windows.Media/DoubleCollection.xml	Update XAML Resources link.
xml/System.Windows.Media.Media3D/GeneralTransform3DCollection.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/VectorAnimation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/Vector3DAnimation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/ThicknessAnimation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/SizeAnimation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/SingleAnimation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/Rotation3DAnimation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/RectAnimation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/QuaternionAnimation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/PointAnimation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/Point3DAnimation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/Int64Animation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/Int32Animation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/Int16Animation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/DoubleAnimation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/DecimalAnimation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/ColorAnimation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/ByteAnimation.xml	Update XAML Resources link.
xml/System.Windows.Media.Animation/AnimationTimeline.xml	Update XAML Resources link.
xml/System.Windows.Markup/DictionaryKeyPropertyAttribute.xml	Update XAML Resources link + markdown list formatting.
xml/System.Windows.Controls/UserControl.xml	Update links + normalize markdown whitespace.
xml/System.Windows.Controls/TabControl.xml	Update XAML Resources link + XAML Values formatting.
xml/System.Windows.Controls/Slider.xml	Update “Styles and Templates” link anchor.
xml/System.Windows.Controls/ScrollViewer.xml	Update “Styles and Templates” link anchor.
xml/System.Windows.Controls/Page.xml	Update XAML Resources link.
xml/System.Windows.Controls/HeaderedItemsControl.xml	Update XAML Resources link(s).
xml/System.Windows.Controls/HeaderedContentControl.xml	Update XAML Resources link(s).
xml/System.Windows.Controls/GroupStyle.xml	Update XAML Resources link.
xml/System.Windows.Controls/GridViewHeaderRowPresenter.xml	Update styling + XAML Resources links.
xml/System.Windows.Controls/GridViewColumn.xml	Update styling + XAML Resources links.
xml/System.Windows.Controls/GridView.xml	Update styling + XAML Resources links.
xml/System.Windows.Controls/GridSplitter.xml	Update styling + XAML Resources links.
xml/System.Windows.Controls/Decorator.xml	Update XAML overview link.
xml/System.Windows.Controls/DatePicker.xml	Update XAML Resources link.
xml/System.Windows.Controls/DataGridTemplateColumn.xml	Update Styling and Templating link.
xml/System.Windows.Controls/ControlTemplate.xml	Update Styling and Templating link.
xml/System.Windows.Controls/Control.xml	Update Styling and Templating link.
xml/System.Windows.Controls/ContentControl.xml	Update XAML overview + XAML Resources links.
xml/System.Windows.Controls/Calendar.xml	Update XAML Resources link(s).
xml/System.Windows.Controls.Primitives/TickBarPlacement.xml	Update “Styles and Templates” link anchor.
xml/System.Windows.Controls.Primitives/TickBar.xml	Update “Styles and Templates” link anchor.
xml/System.Windows.Controls.Primitives/StatusBar.xml	Update “Styles and Templates” link anchor.
xml/System.Windows.Controls.Primitives/GridViewRowPresenterBase.xml	Update XAML Resources link (but currently malformed).
xml/System.Threading/WaitHandle.xml	Update threading article links to new slugs.
xml/System.Threading/Semaphore.xml	Update semaphore article links to new slug.
xml/System.Threading/ReaderWriterLock.xml	Update reader-writer locks article links to new slug.
xml/System.Threading/Mutex.xml	Update mutexes article links to new slug.
xml/System.Threading/Monitor.xml	Update threading features article link slug.
xml/System.Threading/ManualResetEvent.xml	Update sync primitives article link slug(s).
xml/System.Threading/LockCookie.xml	Removed broken related link (consider replacing).
xml/System.Threading/Interlocked.xml	Update sync primitives article link slug(s).
xml/System.Threading/EventWaitHandle.xml	Update sync primitives article link slug(s).
xml/System.Threading/AutoResetEvent.xml	Update sync primitives article link slug(s).
xml/System.Collections.Specialized/NotifyCollectionChangedAction.xml	Remove external documentation link.

[Copilot]

The updated XAML Resources link appears malformed (/dotnet/desktop/wpf/xaml/-resources-define). This looks like an accidental path edit and will likely 404. Please update it to the intended XAML resources article (for example, the same /dotnet/desktop/wpf/systems/xaml-resources-how-to-define-and-reference link used elsewhere in this PR).

Suggested change

	A markup extension that identifies how to reference the template resource, either `StaticResource` or `DynamicResource`. See [XAML Resources](/dotnet/desktop/wpf/xaml/-resources-define).
	A markup extension that identifies how to reference the template resource, either `StaticResource` or `DynamicResource`. See [XAML Resources](/dotnet/desktop/wpf/systems/xaml-resources-how-to-define-and-reference).

[Copilot]

This change removes the "Reader-Writer Locks" related article link entirely. Since other updated threading docs in this PR switch to the new slug /dotnet/standard/threading/reader-writer-locks, consider updating the link here instead of dropping it so the related-links section stays consistent and still points readers to the relevant guidance.

Suggested change

	<related type="Article" href="/dotnet/standard/threading/managed-threading-basics">Managed Threading</related>
	<related type="Article" href="/dotnet/standard/threading/managed-threading-basics">Managed Threading</related>
	<related type="Article" href="/dotnet/standard/threading/reader-writer-locks">Reader-Writer Locks</related>