Update data refresh description on DirectoryInfo.Create (#4240)

* Update data refresh description on DirectoryInfo.Create

* revert line in Refresh

Author: carlossanlop

xml/System.IO/DirectoryInfo.xml

@@ -221,7 +221,10 @@
           <format type="text/markdown"><![CDATA[  
   
 ## Remarks  
+
  If the directory already exists, this method does nothing.  
+
+ If the directory did not exist before calling this method, then any cached attribute information about the directory will be flushed if the creation is successful.  
   
  For a list of common I/O tasks, see [Common I/O Tasks](~/docs/standard/io/common-i-o-tasks.md).  
   

xml/System.IO/FileSystemInfo.xml

@@ -1285,8 +1285,7 @@ On Unix platforms that do not support creation or birth time, this property retu
   
 ## Remarks  
  `FileSystemInfo.Refresh` takes a snapshot of the file from the current file system. `Refresh` cannot correct the underlying file system even if the file system returns incorrect or outdated information. This can happen on platforms such as Windows 98.  
-  
- Calls must be made to `Refresh` before attempting to get the attribute information, or the information will be outdated.  
+  Calls must be made to `Refresh` before attempting to get the attribute information, or the information will be outdated.  
   
  ]]></format>
         </remarks>