Add Lerp algorithm info (#4503)

* add breaking change info

Author: gewarren

xml/System.Numerics/Vector2.xml

@@ -951,7 +951,15 @@
         <param name="amount">A value between 0 and 1 that indicates the weight of <paramref name="value2" />.</param>
         <summary>Performs a linear interpolation between two vectors based on the given weighting.</summary>
         <returns>The interpolated vector.</returns>
-        <remarks>To be added.</remarks>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks
+
+The behavior of this method changed in .NET 5.0. For more information, see [Behavior change for Vector2.Lerp and Vector4.Lerp](/dotnet/core/compatibility/3.1-5.0#behavior-change-for-vector2lerp-and-vector4lerp).
+ 
+          ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="Max">

xml/System.Numerics/Vector4.xml

@@ -1037,7 +1037,15 @@
         <param name="amount">A value between 0 and 1 that indicates the weight of <paramref name="value2" />.</param>
         <summary>Performs a linear interpolation between two vectors based on the given weighting.</summary>
         <returns>The interpolated vector.</returns>
-        <remarks>To be added.</remarks>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks
+
+The behavior of this method changed in .NET 5.0. For more information, see [Behavior change for Vector2.Lerp and Vector4.Lerp](/dotnet/core/compatibility/3.1-5.0#behavior-change-for-vector2lerp-and-vector4lerp).
+ 
+          ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="Max">