Automatically port System.IO.Pipelines.PipeReader remarks (#3685)

Author: carlossanlop

xml/System.IO.Pipelines/PipeReader.xml

@@ -85,7 +85,19 @@ The memory for the consumed data will be released and no longer available. The <
       <Docs>
         <param name="consumed">Marks the extent of the data that has been successfully processed.</param>
         <summary>Moves forward the pipeline's read cursor to after the consumed data, marking the data as processed.</summary>
-        <remarks>To be added.</remarks>
+        <remarks>
+          <format type="text/markdown"><![CDATA[
+
+## Remarks
+
+The memory for the consumed data will be released and no longer available.
+
+The <xref:System.IO.Pipelines.ReadResult.Buffer> previously returned from <xref:System.IO.Pipelines.PipeReader.ReadAsync(System.Threading.CancellationToken)> must not be accessed after this call.
+
+The examined data communicates to the pipeline when it should signal more data is available.
+
+          ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="AdvanceTo">
@@ -114,7 +126,19 @@ The memory for the consumed data will be released and no longer available. The <
         <param name="consumed">Marks the extent of the data that has been successfully processed.</param>
         <param name="examined">Marks the extent of the data that has been read and examined.</param>
         <summary>Moves forward the pipeline's read cursor to after the consumed data, marking the data as processed, read and examined.</summary>
-        <remarks>To be added.</remarks>
+        <remarks>
+          <format type="text/markdown"><![CDATA[
+
+## Remarks
+
+The memory for the consumed data will be released and no longer available.
+
+The <xref:System.IO.Pipelines.ReadResult.Buffer> previously returned from <xref:System.IO.Pipelines.PipeReader.ReadAsync(System.Threading.CancellationToken)> must not be accessed after this call.
+
+The examined data communicates to the pipeline when it should signal more data is available.
+
+          ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="AsStream">