Allow reformat SQL

[parisni]

Would be great to have a way to apply python reformating for cell content

[Dubrzr]

Seems more like a Jupyterlab extension, such as https://github.com/ryantam626/jupyterlab_code_formatter or https://github.com/ryantam626/jupyterlab_black. But those only format Python code.
It would mean to fork one of the two and use a sql formatter in python, such as format-sql or sqlparse and install it on Jupyterlab.