add a qbot snippet to close support threads

[torn sphinx]

It would be cool to have a snippet for qbot to tell users how to close a thread. It would look like this:

If your issue is solved, append [solved] to this thread title then archive it.```

[bright marsh]

.. close If your issue is solved, please append [SOLVED] to the beginning of this thread's title. Then, if possible, archive the thread.

[bronze umbra]

Note close (#9456) added successfully.

[bright marsh]

now type ... close when you wanna use it

[torn sphinx]

Thank you