Update .nitignore

Author: LamentXU123

Doc/tools/.nitignore

@@ -27,7 +27,6 @@ Doc/library/os.rst
 Doc/library/pickletools.rst
 Doc/library/profile.rst
 Doc/library/pyexpat.rst
-Doc/library/resource.rst
 Doc/library/select.rst
 Doc/library/smtplib.rst
 Doc/library/socket.rst