wrong operator and fix documentation

src/Controls/src/Core/Button/Button.iOS.cs

@@ -177,8 +177,8 @@ void LayoutButton(UIButton platformButton, Button button, Rect size)
 			var buttonWidthConstraint = button.WidthRequest == -1 ? size.Width : Math.Min(button.WidthRequest, size.Width);
 			var buttonHeightConstraint = button.HeightRequest == -1 ? size.Height : Math.Min(button.HeightRequest, size.Height);
 
-			var titleWidthConstraint = buttonWidthConstraint - (nfloat)padding.Left + (nfloat)padding.Right + ((nfloat)borderWidth * 2);
-			var titleHeightConstraint = buttonHeightConstraint - (nfloat)padding.Top + (nfloat)padding.Bottom + ((nfloat)borderWidth * 2);
+			var titleWidthConstraint = buttonWidthConstraint - (nfloat)padding.Left - (nfloat)padding.Right - ((nfloat)borderWidth * 2);
+			var titleHeightConstraint = buttonHeightConstraint - (nfloat)padding.Top - (nfloat)padding.Bottom - ((nfloat)borderWidth * 2);
 
 			var imageInsets = new UIEdgeInsets();
 			var titleInsets = new UIEdgeInsets();

src/Controls/src/Core/Platform/iOS/Extensions/ButtonExtensions.cs

@@ -19,7 +19,7 @@ public static class ButtonExtensions
 		/// <param name="widthConstraint"></param>
 		/// <param name="heightConstraint"></param>
 		/// <returns>Returns the <see cref="CGRect"/> that contains the button's title.</returns>
-		/// <remarks>The <see cref="NSStringDrawingOptions.UsesDeviceMetrics"/> flag is useful for when there is truncation in the title so we will take the max width of the two bounding rects.</remarks>
+		/// <remarks>The <see cref="NSStringDrawingOptions.UsesDeviceMetrics"/> flag is useful for when there is truncation in the title so we will take the max width of the two bounding rects. The GetBoundingRect method does not always give a great representation of what characters will be visible on the button but will not be needed when the UIButton.Configuration API is implemented. </remarks>
 		internal static CGRect GetTitleBoundingRect(this UIButton platformButton, double widthConstraint, double heightConstraint)
 		{
 			if ((platformButton.CurrentAttributedTitle != null || platformButton.CurrentTitle != null)