Replace <see langword="UInt64" /> tags (dotnet#3907)

* Replace <see langword="UInt64" /> tags * Apply suggestions from code review Co-Authored-By: Jeremy Barton <jbarton@microsoft.com> Co-authored-by: Jeremy Barton <jbarton@microsoft.com>

Author: nxtn

xml/System.Runtime.Serialization/SerializationInfo.xml

@@ -1043,7 +1043,7 @@ End Sub
  </Parameters>
  <Docs>
  <param name="name">The name to associate with the value, so it can be deserialized later.</param>
- <param name="value">The <see langword="UInt64" /> value to serialize.</param>
+ <param name="value">The value to serialize.</param>
  <summary>Adds a 64-bit unsigned integer value into the <see cref="T:System.Runtime.Serialization.SerializationInfo" /> store.</summary>
  <remarks>
  <format type="text/markdown"><![CDATA[ 

xml/System.Xml/XmlConvert.xml

@@ -2457,7 +2457,7 @@ writer.WriteElementString(XmlConvert.EncodeName("Order Detail"),"My order");
  <Docs>
  <param name="value">The value to convert.</param>
  <summary>Converts the <see cref="T:System.UInt64" /> to a <see cref="T:System.String" />.</summary>
- <returns>A string representation of the <see langword="UInt64" />.</returns>
+ <returns>A string representation of the <see cref="T:System.UInt64" />.</returns>
  <remarks>To be added.</remarks>
  </Docs>
  </Member>
@@ -2803,7 +2803,7 @@ writer.WriteElementString(XmlConvert.EncodeName("Order Detail"),"My order");
  <Docs>
  <param name="s">The string to convert.</param>
  <summary>Converts the <see cref="T:System.String" /> to a <see cref="T:System.UInt64" /> equivalent.</summary>
- <returns>A <see langword="UInt64" /> equivalent of the string.</returns>
+ <returns>A <see cref="T:System.UInt64" /> equivalent of the string.</returns>
  <remarks>To be added.</remarks>
  <exception cref="T:System.ArgumentNullException">
  <paramref name="s" /> is <see langword="null" />.</exception>