fix #4158

Author: TylerMSFT

docs/atl-mfc-shared/reference/csimplestringt-class.md

@@ -515,11 +515,7 @@ LPTSTR pstr = str.GetBufferSetLength(3);
 pstr[0] = _T('C');
 pstr[1] = _T('u');
 pstr[2] = _T('p');
-
-// No need for trailing zero or call to ReleaseBuffer()
-// because GetBufferSetLength() set it for us.
-// If we had called GetBuffer() instead of GetBufferSetLength()
-// then we would have needed to call ReleaseBuffer(). 
+str.ReleaseBuffer();
 
 str += _T(" soccer is best!");
 ASSERT(_tcscmp(str, _T("Cup soccer is best!")) == 0);