Allow debugging the REPL locally

[agriyakhetarpal]

The templates/index.html file sets the host to the deployed shell. This restricts developers from testing out changes locally because the REPL is loaded from the online JupyterLite deployment rather than from the local instance.

I was confused with this for a while when I tried to override the Pyodide version and noticed that it still picked up the newer one from GH Pages.

Originally posted by @agriyakhetarpal in #26 (comment)

[ivanistheone]

As a workaround:

Edit templates/index.html to change the value of host from https://www.sympy.org/live to http://127.0.0.1:8000.

via https://github.com/sympy/live/blob/main/README.md?plain=1#L76-L77

(assuming local webserver will run on port 8000)

[ivanistheone]

I suppose we could add a command-line argument to the generateindex.py that automatically does this, somethign like --localdev.

[agriyakhetarpal]

Yes, I've been using that workaround recently, thanks. A CLI sounds good to me!