XML comment fixes.

src/Avalonia.Base/Utilities/MathUtilities.cs

@@ -30,6 +30,7 @@ namespace Avalonia.Utilities
         /// LessThan - Returns whether or not the first double is less than the second double.
         /// That is, whether or not the first is strictly less than *and* not within epsilon of
         /// the other number.
+        /// </summary>
         /// <param name="value1"> The first double to compare. </param>
         /// <param name="value2"> The second double to compare. </param>
         public static bool LessThan(double value1, double value2)
@@ -41,6 +42,7 @@ namespace Avalonia.Utilities
         /// GreaterThan - Returns whether or not the first double is greater than the second double.
         /// That is, whether or not the first is strictly greater than *and* not within epsilon of
         /// the other number.
+        /// </summary>
         /// <param name="value1"> The first double to compare. </param>
         /// <param name="value2"> The second double to compare. </param>
         public static bool GreaterThan(double value1, double value2)
@@ -52,6 +54,7 @@ namespace Avalonia.Utilities
         /// LessThanOrClose - Returns whether or not the first double is less than or close to
         /// the second double.  That is, whether or not the first is strictly less than or within
         /// epsilon of the other number.
+        /// </summary>
         /// <param name="value1"> The first double to compare. </param>
         /// <param name="value2"> The second double to compare. </param>
         public static bool LessThanOrClose(double value1, double value2)
@@ -170,4 +173,4 @@ namespace Avalonia.Utilities
             }
         }
     }
-}
+}

src/Avalonia.Controls/Grid.cs

@@ -1969,7 +1969,7 @@ namespace Avalonia.Controls
         /// </summary>
         /// <param name="definitions">Array of definitions to process.</param>
         /// <param name="finalSize">Final size to lay out to.</param>
-        /// <param name="rows">True if sizing row definitions, false for columns</param>
+        /// <param name="columns">True if sizing column definitions, false for rows</param>
         private void SetFinalSize(
             IReadOnlyList<DefinitionBase> definitions,
             double finalSize,
@@ -2694,9 +2694,9 @@ namespace Avalonia.Controls
         ///                 if the max constraint has higher discrepancy
         ///     null    if proportion doesn't fail a min or max constraint
         /// The discrepancy is the ratio of the proportion to the max- or min-ratio.
-        /// When both ratios hit the constraint,  minRatio < proportion < maxRatio,
+        /// When both ratios hit the constraint,  minRatio &lt; proportion &gt; maxRatio,
         /// and the minRatio has higher discrepancy if
-        ///         (proportion / minRatio) > (maxRatio / proportion)
+        ///         (proportion / minRatio) &gt; (maxRatio / proportion)
         /// </summary>
         private static bool? Choose(double minRatio, double maxRatio, double proportion)
         {
@@ -4063,4 +4063,4 @@ namespace Avalonia.Controls
             private static readonly Pen _evenDashPen;  //  second pen to draw dash
         }   
     }
-}
+}