Update ManualResetEventSlim.xml (#4364)

Author: greggde

xml/System.Threading/ManualResetEventSlim.xml

@@ -800,7 +800,7 @@
       </ReturnValue>
       <Docs>
         <summary>Gets the underlying <see cref="T:System.Threading.WaitHandle" /> object for this <see cref="T:System.Threading.ManualResetEventSlim" />.</summary>
-        <value>The underlying <see cref="T:System.Threading.WaitHandle" /> event object fore this <see cref="T:System.Threading.ManualResetEventSlim" />.</value>
+        <value>The underlying <see cref="T:System.Threading.WaitHandle" /> event object for this <see cref="T:System.Threading.ManualResetEventSlim" />.</value>
         <remarks>
           <format type="text/markdown"><![CDATA[