Update ActivityListener.xml to Fix Typo (#10631)

Author: josephdiniso

xml/System.Diagnostics/ActivityListener.xml

@@ -47,7 +47,7 @@
       </AssemblyInfo>
       <Parameters />
       <Docs>
-        <summary>Construct a new activity listener object to start listeneing to the activity events.</summary>
+        <summary>Construct a new activity listener object to start listening to the activity events.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>