TypeError due to wrong spelling in keyword

[AndreiSavici]

The call to compute_item_matrix function in https://github.com/jupyter/qtconsole/blob/master/qtconsole/completion_html.py#L315 uses the displaywidth keyword, but the implementation in https://github.com/jupyter/qtconsole/blob/master/qtconsole/util.py#L144 has is spelled as displaywith (no second d). This cause a type error when called in the code

[ccordoba12]

Hey @AndreiSavici, thanks for reporting and for finding the solution to this problem.

We'd really appreciate if you could submit a pull request with the fix you described because we're really busy with other things.