`open-cell` (`zo`) should open the correct filetype in cell

[dufferzafar]

If I've opened the current sheet as a jsonl but the cell that I'm on has a CSV url?

Currently I get:

opening http://url/to/file.csv as jsonl
JSONDecodeError: Expecting value: line 1 column 1 (char 0)

Where it tries to open a CSV file as JSONL for some reason.

Originally posted by @dufferzafar in https://github.com/saulpw/visidata/issues/1514#issuecomment-1938786979