Since we do not make use of my own zettelkasten plugin anymore, this
commit is a quick fix to reinstate the functionality of the `vn` alias
in the shell opening the note index.
An issue is that there is now no dedicated function to show or open the
index, so we have to make do with a hardcoded path. Perhaps at some
point I will get around to fixing that issue but until then I am fine
with it just working again.
When switching the current buffer to the Zettelkasten index page
(`<leader>ni`), we now also switch the working directory to the
corresponding notes directory.
Neovim sometimes errors out when enabling spelling without having all
the necessary spellfiles available. This ensures on setting up the
environment that a spellfile is downloaded.
