allow exception in docs' bash input (for Windows devs' local env)

[2bndy5]

In testing my changes to the lib, I found it more convenient to add the metadata tag raises-exception for the input in code-cells.ipynb:

%%bash
for i in 1 2 3
do
    echo $i
done

Since the CI must be using Linux environments, I doubt this would be detrimental to any deployments.

[mgeier]

I don't think we actually need this, see #739.

[2bndy5]

It is needed to build the current docs on Windows. Using WSL is an alternative approach, but it is significantly and noticably slower to execute. Not to mention, its more difficult to install arch-specific dependencies for WSL.

Changes in #739 should work fine as well.

[mgeier]

OK, thanks, I've merged #739.