Grammar fix (#4053)

Added a period to end of the last sentence in the disclaimer.

Author: breyed

xml/System.Threading/Thread.xml

@@ -544,7 +544,7 @@ Main thread: ThreadProc.Join has returned.  Press Enter to end program.
 ## Remarks  
   
 > [!IMPORTANT]
-> The `Thread.Abort` method should be used with caution. Particularly when you call it to abort a thread other than the current thread, you do not know what code has executed or failed to execute when the <xref:System.Threading.ThreadAbortException> is thrown, nor can you be certain of the state of your application or any application and user state that it is responsible for preserving. For example, calling `Thread.Abort` may prevent static constructors from executing or prevent the release of unmanaged resources
+> The `Thread.Abort` method should be used with caution. Particularly when you call it to abort a thread other than the current thread, you do not know what code has executed or failed to execute when the <xref:System.Threading.ThreadAbortException> is thrown, nor can you be certain of the state of your application or any application and user state that it is responsible for preserving. For example, calling `Thread.Abort` may prevent static constructors from executing or prevent the release of unmanaged resources.
 
        ]]></format>
         </remarks>