build error on the master branch

[GiggleLiu]

There is a large chunk of code in patch.jl copied from Pluto, which is hard to maintain. Now it error on the Pluto master branch.

IIUC, it basically added the following two lines.

    notebook_url = address * "edit?id=$(nb.notebook_id)"
    if session.options.server.launch_browser && open_in_default_browser(notebook_url)

Is there any reason for not PRing the patch into Pluto? @Roger-luo @fonsp