Mime type not set for codemirror.

I am using the sql codemirror_mode, which has several mime types associated with it. I would like to use text/x-cassandra. For some output formatting of CQL (for describing objects), I was able to actually get codemirror to render x-cassandra with my own textarea in the output. However, the input cells seem to use a generic sql format, even if I set the mimetype='text/x-cassandra' in the kernel.

Start with the SQL CodeMirror mode and the input-cell handling described in the issue. Compare how the custom output textarea renders text/x-cassandra with how the kernel mimetype is applied to input cells. Done means input cells use the requested Cassandra MIME mode instead of the generic SQL format.

Written by the indexing model from the issue text.