Update summaries for gesture events in InputElement (#20862)

Write new descriptions in <summary> tags to provide more precise definitions of gestures. This is intended to address https://github.com/AvaloniaUI/avalonia-docs/issues/896

src/Avalonia.Base/Input/InputElement.Gestures.cs

@@ -149,7 +149,7 @@ namespace Avalonia.Input
         }
 
         /// <summary>
-        /// Occurs when a pinch gesture occurs on the control.
+        /// Occurs when the user moves two contact points closer together.
         /// </summary>
         public event EventHandler<PinchEventArgs>? Pinch
         {
@@ -158,7 +158,7 @@ namespace Avalonia.Input
         }
 
         /// <summary>
-        /// Occurs when a pinch gesture ends on the control.
+        /// Occurs when the user releases both contact points used in a pinch gesture.
         /// </summary>
         public event EventHandler<PinchEndedEventArgs>? PinchEnded
         {
@@ -167,7 +167,7 @@ namespace Avalonia.Input
         }
 
         /// <summary>
-        /// Occurs when a pull gesture occurs on the control.
+        /// Occurs when the user drags from the edge of a control.
         /// </summary>
         public event EventHandler<PullGestureEventArgs>? PullGesture
         {
@@ -176,7 +176,7 @@ namespace Avalonia.Input
         }
 
         /// <summary>
-        /// Occurs when a pull gesture ends on the control.
+        /// Occurs when the user releases the pointer after a pull gesture.
         /// </summary>
         public event EventHandler<PullGestureEndedEventArgs>? PullGestureEnded
         {
@@ -185,7 +185,7 @@ namespace Avalonia.Input
         }
 
         /// <summary>
-        /// Occurs when a scroll gesture occurs on the control.
+        /// Occurs when the user continuously moves the pointer in the same direction within the control’s boundaries.
         /// </summary>
         public event EventHandler<ScrollGestureEventArgs>? ScrollGesture
         {
@@ -194,7 +194,7 @@ namespace Avalonia.Input
         }
 
         /// <summary>
-        /// Occurs when a scroll gesture inertia starts on the control.
+        /// Occurs within a scroll gesture, when the user releases the pointer, and scrolling continues by transitioning to momentum-based gliding movement.
         /// </summary>
         public event EventHandler<ScrollGestureInertiaStartingEventArgs>? ScrollGestureInertiaStarting
         {
@@ -203,7 +203,7 @@ namespace Avalonia.Input
         }
 
         /// <summary>
-        /// Occurs when a scroll gesture ends on the control.
+        /// Occurs when a scroll gesture has fully stopped, taking into account any inertial movement that continues the scroll after the user has released the pointer.
         /// </summary>
         public event EventHandler<ScrollGestureEndedEventArgs>? ScrollGestureEnded
         {
@@ -212,7 +212,7 @@ namespace Avalonia.Input
         }
 
         /// <summary>
-        /// Occurs when a touchpad magnify gesture occurs on the control.
+        /// Occurs when the user moves two contact points away from each other on a touchpad.
         /// </summary>
         public event EventHandler<PointerDeltaEventArgs>? PointerTouchPadGestureMagnify
         {
@@ -221,7 +221,7 @@ namespace Avalonia.Input
         }
 
         /// <summary>
-        /// Occurs when a touchpad rotate gesture occurs on the control.
+        /// Occurs when the user places two contact points and moves them in a circular motion on a touchpad.
         /// </summary>
         public event EventHandler<PointerDeltaEventArgs>? PointerTouchPadGestureRotate
         {
@@ -230,7 +230,7 @@ namespace Avalonia.Input
         }
 
         /// <summary>
-        /// Occurs when a swipe gesture occurs on the control.
+        /// Occurs when the user rapidly drags the pointer in a single direction across the control.
         /// </summary>
         public event EventHandler<SwipeGestureEventArgs>? SwipeGesture
         {
@@ -239,7 +239,7 @@ namespace Avalonia.Input
         }
 
         /// <summary>
-        /// Occurs when a touchpad swipe gesture occurs on the control.
+        /// Occurs when the user performs a rapid dragging motion in a single direction on a touchpad.
         /// </summary>
         public event EventHandler<PointerDeltaEventArgs>? PointerTouchPadGestureSwipe
         {
@@ -248,7 +248,7 @@ namespace Avalonia.Input
         }
 
         /// <summary>
-        /// Occurs when a tap gesture occurs on the control.
+        /// Occurs when the user briefly contacts and releases a single point, without significant movement.
         /// </summary>
         public event EventHandler<TappedEventArgs>? Tapped
         {
@@ -257,7 +257,7 @@ namespace Avalonia.Input
         }
 
         /// <summary>
-        /// Occurs when a right tap gesture occurs on the control.
+        /// Occurs when the user briefly contacts and releases a single point, without significant movement, using a mechanism on the input device recognized as a right button or equivalent.
         /// </summary>
         public event EventHandler<TappedEventArgs>? RightTapped
         {
@@ -266,7 +266,7 @@ namespace Avalonia.Input
         }
 
         /// <summary>
-        /// Occurs when a hold gesture occurs on the control.
+        /// Occurs when the user makes a single contact, then maintains contact beyond a given time threshold without releasing or making another contact.
         /// </summary>
         public event EventHandler<HoldingRoutedEventArgs>? Holding
         {
@@ -275,7 +275,7 @@ namespace Avalonia.Input
         }
 
         /// <summary>
-        /// Occurs when a double-tap gesture occurs on the control.
+        /// Occurs when the user briefly contacts and releases twice on a single point, without significant movement.
         /// </summary>
         public event EventHandler<TappedEventArgs>? DoubleTapped
         {