Hyphenate allow-listing (dotnet#7438)

Author: gewarren

xml/ns-System.Web.Security.AntiXss.xml

@@ -4,9 +4,10 @@
     <remarks>
       <format type="text/markdown"><![CDATA[  
   
-## Remarks  
- The encoding algorithms look for a prescribed set of characters that are considered safe and encode all other characters. (This is sometimes referred to as "safe-listing" or "allowlisting.")  
-  
+## Remarks
+
+The encoding algorithms look for a prescribed set of characters that are considered safe and encode all other characters. (This is sometimes referred to as "safe-listing" or "allow-listing.")
+
  ]]></format>
     </remarks>
   </Docs>