Update xml/System.Net.Http/MultipartContent.xml

Co-authored-by: Genevieve Warren <[email protected]>

Author: MihaZupan

xml/System.Net.Http/MultipartContent.xml

@@ -53,13 +53,8 @@
   <Docs>
     <summary>Provides a collection of <see cref="T:System.Net.Http.HttpContent" /> objects that get serialized using the multipart/* content type specification.</summary>
     <remarks>
-      <format type="text/markdown"><![CDATA[
-
-## Remarks
-Multipart messages must contain one or more body parts. When a <xref:System.Net.Http.MultipartContent> instance with zero parts is serialized, it's written as a single empty part with no content headers or message body.
-If your server does not support such contents with zero parts, consider conditionally using a different or no `HttpContent`.
-
-]]></format>
+Multipart messages must contain one or more body parts. When a <see cref="T:System.Net.Http.MultipartContent" /> instance with zero parts is serialized, it's written as a single empty part with no content headers or message body.
+If your server doesn't support such contents with zero parts, consider conditionally using a different <see cref="T:System.Net.Http.HttpContent" /> type or no <see cref="T:System.Net.Http.HttpContent" />.
     </remarks>
   </Docs>
   <Members>