Migrate content from MSDN (#3286)

* Migrate content from MSDN

* remove extra spaces

* migrate content from msdn

* migrate from msdn

* small edit

* Apply suggestions from docs review

Co-Authored-By: Ron Petrusha <ronpet@microsoft.com>

* fix param name

Author: mairaw

xml/System.Windows.Xps/XpsDocumentWriter.xml

@@ -199,9 +199,9 @@
         <Parameter Name="args" Type="System.Windows.Documents.Serialization.WritingCancelledEventArgs" />
       </Parameters>
       <Docs>
-        <param name="sender">To be added.</param>
-        <param name="args">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="sender">The source of the event.</param>
+        <param name="args">The event data.</param>
+        <summary>Raises the <see cref="E:System.Windows.Xps.XpsDocumentWriter.WritingCancelled" /> event.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -232,9 +232,9 @@
         <Parameter Name="e" Type="System.Windows.Documents.Serialization.WritingCompletedEventArgs" />
       </Parameters>
       <Docs>
-        <param name="sender">To be added.</param>
-        <param name="e">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="sender">The source of the event.</param>
+        <param name="e">The event data.</param>
+        <summary>Raises the <see cref="E:System.Windows.Xps.XpsDocumentWriter.WritingCompleted" /> event.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -265,9 +265,9 @@
         <Parameter Name="e" Type="System.Windows.Documents.Serialization.WritingPrintTicketRequiredEventArgs" />
       </Parameters>
       <Docs>
-        <param name="sender">To be added.</param>
-        <param name="e">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="sender">The source of the event.</param>
+        <param name="e">The event data.</param>
+        <summary>Raises the <see cref="E:System.Windows.Xps.XpsDocumentWriter.WritingPrintTicketRequired" /> event.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -298,9 +298,9 @@
         <Parameter Name="e" Type="System.Windows.Documents.Serialization.WritingProgressChangedEventArgs" />
       </Parameters>
       <Docs>
-        <param name="sender">To be added.</param>
-        <param name="e">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="sender">The source of the event.</param>
+        <param name="e">The event data.</param>
+        <summary>Raises the <see cref="E:System.Windows.Xps.XpsDocumentWriter.WritingProgressChanged" /> event.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>

xml/System.Xml/XmlTextReader.xml

@@ -2057,10 +2057,20 @@ String dt4 = reader.GetAttribute("dt",http://www.w3.org/2000/xmlns/);
         <Parameter Name="name" Type="System.String" Index="0" FrameworkAlternate="netframework-1.1" />
       </Parameters>
       <Docs>
-        <param name="name">To be added.</param>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
-        <remarks>To be added.</remarks>
+        <param name="name">The qualified name of the attribute.</param>
+        <summary>Gets the value of the attribute with the specified name.</summary>
+        <value>The value of the specified attribute. If the attribute is not found, returns <see langword="null" />.</value>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+  
+This property does not move the reader.
+
+If the reader is positioned on a `DocumentType` node, this method can be used to get the PUBLIC and SYSTEM literals, for example, `reader["PUBLIC"]`.  
+  
+ ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="Item">

xml/System.Xml/XmlValidatingReader.xml

@@ -1284,10 +1284,20 @@ String dt4 = reader.GetAttribute("dt",http://www.w3.org/2000/xmlns/);
         <Parameter Name="name" Type="System.String" Index="0" FrameworkAlternate="netframework-1.1" />
       </Parameters>
       <Docs>
-        <param name="name">To be added.</param>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
-        <remarks>To be added.</remarks>
+        <param name="name">The qualified name of the attribute.</param>
+        <summary>Gets the value of the attribute with the specified name.</summary>
+        <value>The value of the specified attribute. If the attribute is not found, returns <see langword="null" />.</value>
+        <remarks>
+          <format type="text/markdown"><![CDATA[  
+  
+## Remarks  
+  
+This property does not move the reader.
+
+If the reader is positioned on a `DocumentType` node, this method can be used to get the PUBLIC and SYSTEM literals, for example, `reader["PUBLIC"]`.  
+  
+ ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="Item">